Web hosting and domain names come with a lot of jargon. Most glossaries define technical terms with more technical terms.
This one does not. Every definition here is written for someone who builds websites, runs a business online, or is trying to make a hosting decision without a background in IT.
The glossary is organised by topic so you can find related terms together. If you are looking for a specific term, use your browser search function (Ctrl+F or Cmd+F) and type the term you need.
Domain Names and Registration
Domain name The web address people type to find your website. Yourbusiness.com is a domain name. It is a human-readable label that points to your server’s IP address. Domain names work together with hosting but are purchased and managed separately.
TLD (Top Level Domain) The part of the domain name that comes after the final dot. In yourbusiness.com, the TLD is .com. In yourbusiness.co.uk, the TLD is .co.uk. There are over 1,500 domain extensions available today, from standard options like .net and .org to newer ones like .io and .ai.
gTLD (Generic Top Level Domain) A TLD that is not tied to a specific country. .com, .net, .org, .io, .app, and .ai are all gTLDs. They are available to anyone in the world to register without geographic restrictions.
ccTLD (Country Code Top Level Domain) A two-letter TLD assigned to a specific country. .co.uk is the United Kingdom. .de is Germany. .com.au is Australia. Some ccTLDs require local presence to register. Others are open to anyone.
Domain registrar The company you buy your domain name from. Registrars are accredited by ICANN to sell domain names. Namecheap, GoDaddy, Porkbun, and Cloudflare Registrar are examples.
ICANN (Internet Corporation for Assigned Names and Numbers) The non-profit organisation that oversees the global domain name system. It accredits registrars, manages TLD policies, and maintains the root zone database. Think of it as the governing body for how domain names are assigned.
WHOIS is a publicly accessible database that stores registration information for domain names. Without domain privacy protection, your name, address, email, and phone number can be visible to anyone who searches your domain in WHOIS. Protect your personal information and check your domain details instantly with our WHOIS lookup tool: Domain WHOIS Lookup
Domain privacy protection A service that replaces your personal contact details in the WHOIS database with the registrar’s proxy contact information. It hides your name and address from public view. Domain privacy protection does not hide everything though, your domain name, nameservers, and registration dates remain visible.
Nameservers Servers that tell the internet where your website is hosted. When someone types your domain name, their browser asks your nameservers for the IP address of your server. Changing nameservers changes where your domain points.
DNS (Domain Name System) The system that translates domain names into IP addresses. Think of it like a phone book for the internet. Your browser looks up your domain name in the DNS to find which server to connect to.
DNS record An entry in the DNS system that controls how your domain works. Different record types handle different things. Common record types are listed below.
A record A DNS record that points your domain name to an IP address. It is the most common record type and is how your domain finds your web server.
CNAME record (Canonical Name record) A DNS record that points one domain name to another domain name instead of an IP address. Used for subdomains like www.yourdomain.com pointing to yourdomain.com, or for pointing to CDN and third-party services.
MX record (Mail Exchange record) A DNS record that tells the internet where to deliver email for your domain. Without a correct MX record, email sent to your@yourdomain.com will not arrive.
TXT record A DNS record used to store text information. Commonly used for email authentication (SPF, DKIM, DMARC) and for verifying domain ownership with third-party services like Google Search Console.
DNS propagation The time it takes for a DNS change to spread across all the servers on the internet. After you update a DNS record or change nameservers, it can take anywhere from a few minutes to 48 hours for the change to be visible everywhere.
TTL (Time to Live) A value attached to a DNS record that tells servers how long to cache that record before checking for updates. A TTL of 3600 means servers hold the cached record for one hour before rechecking.
Domain transfer Moving your domain name from one registrar to another. It requires an authorisation code (also called an EPP code or auth code) from your current registrar and takes up to seven days to complete. The domain transfer process is straightforward but requires unlocking the domain first.
EPP code (Auth code) A unique code generated by your current registrar that you need to transfer your domain to a different registrar. Think of it as the key that unlocks the domain for transfer.
Domain expiry The date on which your domain registration ends if it is not renewed. After expiry, domains go through grace and redemption periods before being released.
Grace period The period after a domain expires during which you can renew it at the standard price without losing it. Typically 30 to 45 days depending on the registrar.
Redemption period The period after the grace period ends during which you can still recover your domain by paying a redemption fee. Fees typically range from $50 to $300. After this period, the domain enters pending delete.
Pending delete The final five-day stage before an expired domain is released back into the public pool. During this time, the domain cannot be recovered by anyone.
Subdomain A prefix added before your main domain name. blog.yourdomain.com and shop.yourdomain.com are subdomains of yourdomain.com. The difference between subdomains and separate domains affects how search engines treat each section of your site.
Domain authority A metric created by SEO tool providers (not Google) that estimates how well a domain might rank in search results based on the quality and quantity of links pointing to it. It is an approximation, not a direct Google ranking signal. Domain authority can be useful for comparing sites but should not be treated as an official measure.
Web Hosting Types
Web hosting A service that provides storage and computing resources for your website files so they can be accessed on the internet. Without hosting, your website files have no place to live that makes them publicly accessible.
Web hosting and domain names are separate purchases that work together, and understanding how hosting works helps you make better decisions about which plan to choose.
Shared hosting A hosting arrangement where your website shares a server with many other websites. It is the cheapest option. Resources like CPU, RAM, and bandwidth are divided among all sites on the server.
Shared hosting works for low-traffic sites but becomes a limitation as your site grows.
VPS hosting (Virtual Private Server) A hosting arrangement where your website has its own dedicated portion of a server. Other websites may share the same physical machine, but your resources are isolated.
VPS hosting is more reliable and more powerful than shared hosting and suits growing businesses that have outgrown basic plans.
Cloud hosting A hosting arrangement where your website runs across a network of multiple servers rather than a single machine. Resources scale automatically when traffic increases.
Cloud hosting is the most resilient option because if one server has a problem, others take over instantly.
Dedicated server A hosting arrangement where you rent an entire physical server exclusively for your website. No other websites share any resources with you.
Dedicated servers are the highest performance option and the most expensive, suited to large businesses with high-volume workloads or strict compliance requirements.
Managed hosting A hosting arrangement where the provider handles server maintenance, security updates, backups, and technical management for you. You focus on your website. The provider handles the infrastructure. Usually costs more than unmanaged options.
Unmanaged hosting A hosting arrangement where you are responsible for server configuration, software updates, security, and maintenance. More control, lower cost, higher technical requirement.
The managed vs unmanaged VPS comparison explains who each option suits and what the practical differences look like day to day.
Managed WordPress hosting Hosting built specifically for WordPress websites where the provider handles WordPress core updates, security, caching, backups, and staging.
Managed WordPress hosting costs more than standard hosting but removes significant maintenance overhead for business owners who want to focus on their content rather than their server.
Reseller hosting A hosting product that lets you buy hosting resources wholesale and sell them to your own customers under your own brand. Used by web designers and agencies who want to offer hosting as part of their service.
Colocation (colo) A service where you own your physical server hardware but rent space, power, cooling, and network connectivity in a data centre. You manage the hardware. The data centre provides the facility.
Servers and Infrastructure
Server A computer that stores your website files and sends them to visitors when requested. A server runs continuously and is connected to the internet around the clock.
Physical server (bare metal server) An actual physical computer in a data centre, as opposed to a virtualised or cloud environment. When you rent a dedicated server, you are renting physical hardware.
Virtual machine (VM) A software-based simulation of a physical computer. VPS hosting creates virtual machines on physical servers, dividing one physical machine into multiple isolated virtual ones.
Container A lightweight method of isolating applications on a shared operating system. Containers are faster to start than full virtual machines and use resources more efficiently. Many managed WordPress hosts use container technology to isolate each website.
Hypervisor Software that creates and manages virtual machines on a physical server. It allocates hardware resources between virtual machines and keeps them isolated from each other.
Data centre A facility that houses servers, networking equipment, and the infrastructure that supports them. Data centres provide power, cooling, physical security, and network connectivity. Your hosting provider operates in one or more data centres.
Server location The physical geographic location of the server that hosts your website. Server location affects how fast your site loads for visitors. A server in Frankfurt loads faster for users in Germany than a server in the US, which is why choosing a server location close to your main audience directly affects your site performance.
IP address A unique numerical address that identifies a device on the internet. Your server has an IP address. When someone types your domain name, DNS translates it to your server’s IP address.
IPv4 The older version of IP addressing that uses four sets of numbers up to three digits each, separated by dots. Example: 192.168.1.1. The pool of available IPv4 addresses is exhausted, which is why IPv6 was developed.
IPv6 The newer version of IP addressing that uses a much longer format to allow for an enormous number of unique addresses. Most modern hosting supports both IPv4 and IPv6.
Shared IP address An IP address that is shared among multiple websites on the same server. Common on shared hosting plans.
Dedicated IP address An IP address assigned exclusively to your website. Required for some advanced SSL configurations and sometimes useful for email reputation.
Uptime The percentage of time a server is online and accessible. A host that guarantees 99.9% uptime allows for approximately 8.7 hours of downtime per year. Uptime matters more than most business owners realise because even short periods of downtime during busy hours translate directly to lost revenue and lost visitors.
Downtime The period when a server or website is offline and inaccessible to visitors.
SLA (Service Level Agreement) A written contract that defines the service standards a hosting provider must meet, including uptime guarantees, and what compensation you receive if they fail. An uptime guarantee without an SLA is a marketing claim, not a binding commitment.
Bandwidth The amount of data that can be transferred between your server and visitors in a given period. Measured in gigabytes per month. A page that is 2MB in size and receives 10,000 visits uses approximately 20GB of bandwidth.
Storage The amount of disk space available on your server for your website files, database, emails, and backups. Measured in gigabytes or terabytes.
RAM (Random Access Memory) The short-term working memory a server uses to process requests. More RAM allows the server to handle more simultaneous visitors and more complex tasks without slowing down.
CPU (Central Processing Unit) The processor that executes computing tasks on the server. More CPU cores and faster processing speeds allow the server to handle more requests simultaneously.
SSD (Solid State Drive) A storage device with no moving parts that reads and writes data much faster than traditional hard drives. Most modern hosting uses SSD or NVMe storage.
NVMe (Non-Volatile Memory Express) A faster type of SSD that uses a different connection interface. NVMe storage is significantly faster than standard SSD for database-intensive workloads like WordPress.
HDD (Hard Disk Drive) An older storage technology that uses spinning magnetic disks. Much slower than SSD or NVMe. Rarely used in modern hosting but still found in some older or budget infrastructure.
CDN (Content Delivery Network) A network of servers distributed across multiple geographic locations that delivers your website content to visitors from the server closest to them. This reduces load times for visitors far from your main server. Read how caching and CDN improve website speed.
Anycast A networking approach where the same IP address is announced from multiple server locations. Traffic is automatically routed to the nearest location. Cloudflare uses Anycast for their DNS and CDN network.
Load balancer A system that distributes incoming traffic across multiple servers. When one server gets too much traffic, the load balancer sends new requests to less busy servers. Used to prevent any single server from becoming overwhelmed.
Failover An automatic process where traffic is redirected to a backup server if the primary server fails. Failover is a key component of high-availability hosting setups.
Redundancy Having backup systems in place so that if one component fails, another takes over without interruption. Redundant power supplies, network connections, and servers prevent single points of failure.
Performance Terms
Page load time The total time it takes for a webpage to fully load in a visitor’s browser. Measured in seconds. Shorter is always better.
TTFB (Time to First Byte) The time between a browser sending a request to a server and receiving the first byte of a response. TTFB measures how fast your server responds. A slow TTFB usually indicates a server performance or caching issue.
Caching Storing a saved version of content so it can be delivered quickly without generating it fresh each time. Server-level caching is one of the most effective ways to speed up a WordPress site. How caching works and why it matters is something every site owner benefits from understanding before evaluating hosting plans.
Browser cache A copy of website files stored on a visitor’s own device. When a returning visitor loads your site, cached files load instantly from their device rather than being downloaded again from your server.
Server cache A saved version of a webpage stored on the server. Instead of generating the page from scratch for each visitor, the server sends the cached version, which is much faster.
Object cache A system that stores the results of database queries in fast memory so they do not need to be recalculated for every request. Redis and Memcached are common object caching systems used for WordPress.
Redis An in-memory data storage system used for object caching. It stores database query results so WordPress can retrieve them from memory instead of querying the database repeatedly.
Memcached Another in-memory caching system similar to Redis. Used to reduce database load and speed up dynamic websites.
PHP A programming language that WordPress and many other websites are built on. Your hosting server must run PHP. The version of PHP your server uses affects both performance and security. PHP 8.1 and above is recommended for WordPress.
Latency The delay between a request being made and a response being received. Latency is affected by physical distance between the user and the server and by network congestion.
HTTP (HyperText Transfer Protocol) The protocol that browsers use to communicate with web servers. When you visit a website, your browser sends HTTP requests to the server and receives HTTP responses.
HTTPS The secure version of HTTP that encrypts communication between your browser and the server using SSL/TLS. All modern websites should use HTTPS. Browsers display a security warning for sites that do not.
HTTP/2 A newer version of HTTP that loads multiple resources simultaneously instead of one at a time. Significantly faster than HTTP/1.1 for modern websites.
HTTP/3 An even newer version that further improves on HTTP/2, especially for users on unreliable or high-latency connections. Adoption is growing.
Gzip compression A method of compressing web files before sending them to a visitor’s browser. Compressed files transfer faster. Most modern servers and browsers support Gzip automatically.
Brotli compression A newer compression method that achieves better compression ratios than Gzip in many cases. Supported by modern browsers and increasingly adopted by hosting providers.
LCP (Largest Contentful Paint) A Core Web Vital metric that measures how long it takes for the main content of a page to become visible. A good LCP is under 2.5 seconds. Your hosting infrastructure is one of the biggest factors in LCP because a slow server response time directly delays when content appears, which is why a high PageSpeed score does not always mean fast real user experience.
CLS (Cumulative Layout Shift) A Core Web Vital metric that measures how much page content moves unexpectedly while loading. A high CLS means elements shift around and visitors click the wrong thing. A good CLS score is under 0.1.
INP (Interaction to Next Paint) A Core Web Vital metric that measures how quickly a page responds to user interactions like clicks and taps. A good INP is under 200 milliseconds.
Core Web Vitals A set of performance metrics defined by Google that measure real user experience on a webpage. They are used as a ranking factor in Google Search. LCP, CLS, and INP are the three Core Web Vitals.
Security Terms
SSL certificate A digital certificate that enables encrypted communication between a visitor’s browser and your server. It is what creates the padlock in the browser address bar and enables HTTPS. Most hosts include SSL certificates free on all plans, and any host that charges extra for one is behind the standard.
TLS (Transport Layer Security) The encryption protocol that SSL certificates use. TLS 1.2 and 1.3 are current standards. Older versions (TLS 1.0 and 1.1) are insecure and should not be in use.
Firewall A security system that monitors incoming and outgoing network traffic and blocks connections that appear malicious. A server-level firewall is the first line of defence against attacks. Web hosting firewalls vary significantly between providers, and knowing what to look for helps you evaluate whether a plan’s security is adequate.
WAF (Web Application Firewall) A firewall specifically designed to protect web applications. It filters HTTP traffic and blocks attacks like SQL injection and cross-site scripting before they reach your site. A WAF should be included as standard on any business hosting plan, not sold as a premium add-on.
DDoS attack (Distributed Denial of Service) An attack where a large number of requests flood a server simultaneously, overwhelming it and causing it to go offline. DDoS protection should be always-on at the infrastructure level, not a reactive measure that kicks in after the attack has already taken your site down.
Brute force attack An attack where a script repeatedly tries different username and password combinations to gain access to a login. Blocked by limiting login attempts, using strong passwords, and enabling two-factor authentication.
Malware Malicious software. On a website, malware can redirect visitors, steal data, display spam, or be used to attack other sites. Good hosting includes automated malware scanning and removal.
SQL injection A type of attack where malicious code is inserted into a database query through a form or URL parameter. A WAF blocks most SQL injection attempts before they reach the database.
Cross-site scripting (XSS) A type of attack where malicious scripts are injected into a webpage and run in other users’ browsers. WAFs and content security policies help prevent XSS attacks.
Two-factor authentication (2FA) A security measure that requires a second verification step beyond your password to log in. Even if your password is stolen, an attacker cannot access your account without the second factor. Setting up two-factor authentication on your hosting account takes five minutes and is one of the most effective security steps available.
PCI DSS (Payment Card Industry Data Security Standard) A security standard for any business that accepts credit or debit card payments. It requires specific infrastructure, encryption, and access controls. Your hosting environment must support PCI compliance if you process payments.
GDPR (General Data Protection Regulation) A European regulation that governs how personal data is collected, stored, and processed. If your site has EU visitors, GDPR affects your hosting decisions around data location, encryption, and the agreement you must have with your hosting provider as a data processor.
DPA (Data Processing Agreement) A contract between you and your hosting provider (as a data processor) required under GDPR. It defines how your data is handled, who can access it, and what happens in a breach.
SSL/TLS handshake The process by which a browser and server establish an encrypted connection. It happens automatically when you visit an HTTPS site. A slow handshake adds to page load time.
Certificate authority (CA) An organisation that issues SSL certificates and vouches for their authenticity. Let’s Encrypt is a free CA. DigiCert and Comodo are paid CAs.
Let’s Encrypt A free, automated certificate authority that provides free SSL certificates. Most reputable hosting providers include Let’s Encrypt certificates as standard and renew them automatically.
DNSSEC (DNS Security Extensions) A security extension to the DNS system that uses digital signatures to verify that DNS responses are authentic and have not been tampered with. Protects against DNS spoofing attacks.
SPF (Sender Policy Framework) A DNS record that specifies which servers are authorised to send email from your domain. Helps prevent email spoofing and improves email deliverability.
DKIM (DomainKeys Identified Mail) An email authentication method that adds a digital signature to outgoing emails. Receiving servers verify the signature to confirm the email genuinely came from your domain.
DMARC (Domain-based Message Authentication Reporting and Conformance) An email policy that tells receiving servers what to do with emails that fail SPF or DKIM checks. It can instruct servers to quarantine or reject unauthenticated emails and sends reports back to you.
Blacklist A list of IP addresses or domains that have been flagged for sending spam or malicious content. Being on a blacklist can cause your emails to be blocked or your site to be flagged by browsers.
Backup A saved copy of your website files and database that can be used to restore your site if something goes wrong. Good hosting includes daily automated backups stored separately from the main server.
Restore point A specific backup that you can use to roll your website back to a previous state. A restore point from before a bad update or hack allows you to recover quickly.
Control Panels and Management Tools
cPanel The most widely used web hosting control panel. It provides a graphical interface for managing your website files, databases, email accounts, and hosting settings. Used on most shared and VPS hosting plans.
Plesk An alternative hosting control panel to cPanel. More commonly used on Windows servers but also available on Linux. Offers similar functionality to cPanel.
WHM (WebHost Manager) A server-level control panel used alongside cPanel. It allows hosting providers and resellers to manage multiple cPanel accounts on one server.
FTP (File Transfer Protocol) A method of transferring files between your computer and your server. Used to upload website files directly. FTP sends data without encryption, which is why SFTP is preferred.
SFTP (Secure File Transfer Protocol) An encrypted version of FTP. It transfers files between your computer and server securely. Always use SFTP rather than FTP when available.
File manager A browser-based tool in your hosting control panel that lets you browse, upload, edit, and delete files on your server without using FTP software.
SSH (Secure Shell) An encrypted protocol for accessing and controlling your server through a command line. Required for advanced server management. Most managed hosting plans do not expose SSH to end users, but VPS and dedicated hosting typically do.
Root access The highest level of access on a Linux server. With root access, you can install software, change server configuration, and make system-wide changes. Usually only available on VPS and dedicated hosting.
phpMyAdmin A browser-based tool for managing MySQL databases. It lets you view, edit, and run queries on your database without using command-line tools.
MySQL The most widely used open-source database system. WordPress stores all its content in a MySQL database. Your hosting server runs MySQL to support the database.
MariaDB An open-source fork of MySQL that is compatible with MySQL but often faster in benchmarks. Many hosting providers run MariaDB in place of MySQL.
Softaculous An auto-installer tool available in cPanel and other control panels. It lets you install WordPress, Joomla, Drupal, and dozens of other applications with a single click.
Staging environment A copy of your live website where you can test changes, updates, and new features without affecting the real site. Changes on staging are only visible to you until you push them live. Essential for any business website.
Git A version control system used by developers to track changes in code. Some hosting environments support Git deployment, allowing developers to push code changes directly from their development tools.
Email Hosting Terms
Email hosting A service that provides the infrastructure for your email accounts. Separate from web hosting in many cases, though some providers offer both.
SMTP (Simple Mail Transfer Protocol) The protocol used to send email. Your email client uses SMTP to send messages to your mail server, which then forwards them to the recipient.
POP3 (Post Office Protocol 3) A protocol for retrieving email from a mail server. POP3 downloads emails to your device and typically removes them from the server. Useful if you only check email from one device.
IMAP (Internet Message Access Protocol) A protocol for accessing email that leaves messages on the server and syncs across multiple devices. Preferred over POP3 for most users because email is accessible from any device.
MX record A DNS record that tells the internet which server handles email for your domain. If your MX records are wrong, email to your@yourdomain.com will not arrive.
Email deliverability How successfully your emails reach recipients’ inboxes rather than spam folders. Affected by your server’s IP reputation, SPF, DKIM, and DMARC settings.
Spam filter A system that analyses incoming email and decides whether it is likely spam. Email that triggers spam filters is diverted to the spam folder or rejected entirely.
Transactional email Automated email sent in response to a user action. Password reset emails, order confirmations, and membership welcome emails are all transactional emails. Hosting-provided email is not ideal for transactional email at volume.
Webmail A browser-based email client that lets you access your email without installing a separate email application. Roundcube and Squirrelmail are common webmail applications included with cPanel.
WordPress Specific Terms
WordPress The most widely used content management system in the world. It is open-source software that you install on your own hosting to build and manage a website. WordPress.org is the self-hosted version.
WordPress.com vs WordPress.org WordPress.com is a hosted platform where WordPress is managed for you with restrictions on plugins and customisation. WordPress.org is the free software you download and install on your own hosting with full control. They share a name but are very different products.
Theme A collection of files that controls the visual appearance and layout of a WordPress site. Themes can be free or paid and are installed through the WordPress dashboard.
Plugin An add-on that extends the functionality of WordPress. There are over 60,000 free and paid plugins available. Plugins add features like contact forms, e-commerce, SEO tools, and security.
WooCommerce The most popular e-commerce plugin for WordPress. It turns a WordPress site into an online store with product listings, shopping cart, and checkout functionality.
WordPress multisite A feature that allows you to run multiple WordPress websites from a single WordPress installation. Used by networks, agencies, and organisations managing many sites.
Child theme A theme that inherits the functionality of a parent theme but can be customised independently. Changes to a child theme are not overwritten when the parent theme updates.
PHP memory limit The maximum amount of memory WordPress can use for a single process. A low memory limit can cause errors, especially on sites with many plugins. Typically set in your hosting configuration.
Billing and Contract Terms
Auto-renewal A setting that automatically charges your payment method and renews your hosting or domain before it expires. Prevents accidental loss of your domain or hosting due to a missed renewal.
Promotional pricing A discounted price offered for the first term of a hosting or domain purchase. Renewal prices are almost always higher than promotional prices. Always check the renewal rate before signing up.
Renewal price The standard price your hosting or domain charges after the initial promotional period ends. Can be two to four times higher than the introductory rate.
Money-back guarantee A period during which you can cancel your hosting and receive a refund. Most providers offer 30 days. Domain registrations are usually excluded from refunds.
Bandwidth overage An additional charge applied when your website uses more data transfer than your plan includes. More common on older hosting plans. Many modern plans include unlimited bandwidth with fair use limits.
Fair use policy Terms that define what counts as normal, acceptable resource usage on plans that advertise unlimited features. Resources are not truly unlimited. The fair use policy defines the actual limits, and most beginners misunderstand what unlimited hosting actually means before discovering these clauses after signing up.
Uptime guarantee A commitment from your hosting provider that your site will be available for a stated percentage of time. Must be backed by an SLA to be meaningful.
SLA (Service Level Agreement) A written contract that defines the service standards your host must meet and what compensation applies if they fail. An uptime guarantee without an SLA is just marketing.
Data retention How long your hosting provider keeps your data after account cancellation. Many providers delete data within 30 days of cancellation. Export everything before cancelling.
Lock-in period A minimum contract duration during which you cannot cancel without penalty. Common on some managed hosting contracts. Check for lock-in terms before signing.
Networking Terms
Ping A test that measures the time it takes for a small data packet to travel from one point to another and back. Measured in milliseconds. Lower ping means lower latency.
Traceroute A diagnostic tool that shows the path data takes from your computer to a server, listing each hop along the way and the time each hop takes. Used to identify where network slowdowns occur.
Port A numbered channel through which network traffic flows. Different services use different ports. Port 80 is HTTP. Port 443 is HTTPS. Port 22 is SSH. Port 25 is SMTP.
Packet A small unit of data transmitted over a network. All data sent over the internet is broken into packets, sent separately, and reassembled at the destination.
Proxy server A server that acts as an intermediary between a user and a destination server. CDNs use proxy servers to deliver content from servers close to the user.
Reverse proxy A server that sits in front of your web server and handles incoming requests on its behalf. Used for load balancing, caching, and SSL termination. Cloudflare and Nginx can act as reverse proxies.
Load time The total time from when a user requests a page to when it is fully loaded in their browser. Affected by server speed, file sizes, number of requests, and the user’s connection speed.
Nameserver (NS record) A DNS record that specifies which server is authoritative for a domain’s DNS. Changing nameservers transfers DNS management from one provider to another. This is how you point your domain to a hosting provider or Cloudflare.
Autonomous System (AS) A large network or group of networks with a single routing policy managed by one organisation. Internet service providers and large hosting providers each have their own autonomous systems.
BGP (Border Gateway Protocol) The routing protocol that manages how data is routed between different autonomous systems on the internet. Relevant to hosting because providers with direct BGP peering often have better network performance.
Final Note
This glossary covers the terms that come up most often when buying, setting up, and managing hosting and domains. If you come across a term that is not here, the comments section is always open.
The best way to apply this knowledge is through our practical guides. Start with how web hosting works, then how to choose a web hosting plan, and browse our hosting reviews when you are ready to pick a provider.
