Glossary
the jargon, in plain english.
Hosting, domains, DNS, email and security are full of acronyms that everyone uses and nobody explains. Here is what they actually mean, written for the person paying the bill rather than the person configuring the server.
hosting
- Web hosting
- The service that stores your website's files and serves them to visitors' browsers. Without hosting, a domain name points at nothing — the hosting is the actual computer your site lives on.
- Cloud server (VPS)
- A dedicated slice of a server's resources — processor, memory and disk — reserved for you alone rather than shared with other customers. Often called a VPS (virtual private server); you get more control and capacity in exchange for managing more of it yourself.
- Plesk
- A control panel for managing a website, its email, databases and SSL certificates from one web interface, without touching the command line. It is one of the two main hosting control panels, alongside cPanel.
- cPanel
- The other widely used hosting control panel, long the default on Linux shared hosting. It does the same job as Plesk — managing sites, email and databases through a browser — with a different layout.
- PHP
- The programming language a large share of the web is built in, WordPress included. The PHP version your host runs matters: older themes and plugins can break on a newer one, so being able to choose the version is useful.
- MySQL / database
- A database is where a site stores anything that is not a flat file — posts, products, users, settings. MySQL, and its drop-in cousin MariaDB, is the database system most shared hosting and most of WordPress rely on.
- Node.js
- A runtime that lets JavaScript run on the server rather than only in the browser, used for apps and APIs built with frameworks like Next.js or Express. Running it on shared hosting needs specific support and is not something every plan offers.
- Git deployment
- A way of publishing changes to a site by pushing them to a Git repository, from which the server pulls the new code. It replaces uploading files by hand and makes rolling back to a previous version straightforward.
- Staging
- A private copy of a live site where you can test changes — an update, a new plugin, a redesign — before they reach visitors. It is the difference between a bad update breaking a test copy and breaking your public site.
- WordPress
- The most widely used website platform in the world, a content-management system written in PHP. It powers a large share of the web, which also makes it a frequent target, so keeping it and its plugins updated matters.
- Backups
- Copies of your site's files and database taken on a schedule, so a broken update, a hack or a mistake can be undone by restoring an earlier version. A backup you have never tested restoring is only half a backup.
- Reseller hosting
- A hosting account divided into several separate accounts that you manage and sell on under your own name — the usual setup for a designer or agency hosting client sites. You get your own customers without running the servers.
- Migration
- The process of moving a website — its files, database, email and DNS — from one host to another. Done in the right order, with the domain switched only after the new copy is tested, it happens with little or no downtime.
domains & dns
- DNS
- The internet's address book. DNS translates a domain name people can remember into the server addresses machines actually use, and holds the records that route a domain's website and email.
- A record
- The DNS record that points a domain, or a subdomain, at a server's IPv4 address — the record that decides which server serves the website. Its IPv6 equivalent is the AAAA record.
- CNAME record
- A DNS record that points one name at another name rather than at an address — an alias. Commonly used for www or to point a subdomain at an external service.
- MX record
- The DNS record that says where a domain's email should be delivered. Wrong or missing MX records are the usual reason email suddenly stops arriving.
- TXT record
- A free-text DNS record used to publish small pieces of information for other systems to read. In practice this is where SPF, DKIM and DMARC live, along with domain-verification codes.
- Nameserver
- The servers responsible for answering DNS queries for a domain — in effect, who is in charge of its records. Pointing a domain's nameservers at a host hands that host control of all its DNS at once.
- TTL
- Time to live: how long, in seconds, other servers may cache a DNS record before checking again. Lowering it before a planned change means the change propagates in minutes rather than up to a day.
- Propagation
- The delay while a DNS change spreads across the internet's caches. During the window some visitors see the new setting and some the old — normal, not a fault — and it is governed by the record's TTL.
- WHOIS
- A public lookup showing who registered a domain, when it was created and when it expires. Some registries let individuals hide their personal address; business registrations are generally published.
- EPP / auth code
- A password-like code, also called an auth code or transfer key, that authorises moving a domain from one registrar to another. You get it from your current registrar and give it to the new one, which stops anyone transferring your domain without permission.
- IPS tag
- The Nominet equivalent of a transfer code, used for .uk domains. Each registrar has an IPS tag, and moving a .uk domain means asking your current registrar to change the tag to the new one's.
- Registrar
- A company accredited to register domain names on your behalf and hold them for you. Where you bought your domain is your registrar; it is not necessarily the same company as your web host.
- TLD
- Top-level domain: the last part of a domain name — .com, .co.uk, .uk, .org. Some are open to anyone; others carry conventions about who they suit.
- Subdomain
- A prefix on your domain that can point somewhere of its own — shop.example.com, or blog.example.com. Subdomains are free to create and are controlled with their own DNS records.
- SPF
- Sender Policy Framework: a DNS record listing which servers are allowed to send email using your domain. A domain may have only one SPF record — a second one invalidates the first.
- DKIM
- DomainKeys Identified Mail: a cryptographic signature added to your outgoing email, with the matching key published in DNS, so receivers can confirm the message is genuinely yours and was not altered in transit.
- DMARC
- A DNS record that tells receiving servers what to do with email that fails SPF and DKIM checks, and asks them to report back. It ties the other two together and is best introduced in monitor-only mode first.
- IMAP / POP
- The two protocols for reading email from a mailbox. IMAP keeps mail on the server and syncs every device to the same state; POP downloads mail to one device and traditionally removes it from the server. IMAP is what almost everyone wants now.
- Microsoft 365
- Microsoft's subscription bundle that includes hosted business email, on Exchange Online, alongside apps like Outlook, Word and Teams. A common alternative to email hosted with your website.
- Exchange
- Microsoft's business email system, which handles mail, shared calendars and contacts and syncs them across devices. Most people meet it as the email half of Microsoft 365 rather than as software they run themselves.
security
- SSL / TLS
- The technology that encrypts the connection between a visitor's browser and your site, so data cannot be read in transit. TLS is the current version; most people still call it SSL, and it is what puts the padlock and the s in https.
- HTTPS
- The secure version of the web's protocol, where the connection is encrypted with TLS. Browsers now flag plain http sites as not secure, so https — which needs a valid certificate — is effectively required.
- WAF
- Web application firewall: a filter that sits in front of a website and blocks malicious requests — common attack patterns, bad bots, known exploits — before they reach the application. Cloudflare is one widely used example.
- Malware scanning
- Automated checking of a site's files for known malicious code, backdoors and injected content, so a compromise is caught and flagged rather than left running quietly. It detects problems; it does not replace keeping software updated.
- Fail2ban
- A server tool that watches log files for repeated failed logins and other abuse, then temporarily blocks the offending IP address. It is a quiet, standard defence against brute-force password attacks.
- DDoS
- A distributed denial-of-service attack: flooding a site or server with traffic from many machines at once to knock it offline. Defending against a large one needs network-level filtering, which is one reason sites sit behind services like Cloudflare.
performance
- CDN
- Content delivery network: a global set of servers that cache copies of your site's static files and serve each visitor from a location near them. It speeds the site up and absorbs traffic that would otherwise hit your server directly.
- Cloudflare
- A widely used service that sits between visitors and your site, providing a CDN, DDoS protection and a web application firewall. It can speed a site up and shield it, though it also becomes another layer to configure correctly.
- Uptime
- The share of time a site or server is up and reachable, usually quoted as a percentage. The gap between 99.9% and 99% is larger than it looks — roughly nine hours of downtime a year versus more than three days.
- Bandwidth
- The volume of data transferred between your site and its visitors over a period, usually measured per month. Text-heavy sites use little; those serving lots of images, video or downloads use far more.
- SSD / NVMe
- Types of solid-state storage, which have no moving parts and are far faster than the spinning hard disks they replaced. NVMe is a newer, faster class of SSD; both make a database-driven site noticeably quicker to respond.
- RAM
- A server's short-term working memory, used to run active processes and cache data. Too little is a common cause of a site slowing down or failing under load, particularly with heavier platforms.
past the definition and want the how to?
Our guides go a step further than these entries — pointing a domain, fixing email deliverability, moving a site without downtime. Or see the hosting behind the jargon.