Glossary
Domains & DNS: terms A–Z
Every domain and DNS term explained in plain English — from A record to zone file.
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Domains and DNS have a lot of unfamiliar vocabulary. This page is your reference. You don't need to memorize it — just know it's here when someone says "update your CNAME" and you want to know what that means.
Quick summary
This page defines 50+ domain and DNS terms alphabetically. Use Ctrl+F / Cmd+F to jump to any term. For step-by-step guides, see the Domains & DNS section.
A–C
| Term | Plain-English definition |
|---|---|
| A record | The most common DNS record. Points your domain name to a specific IP address (server). "A" stands for Address. |
| AAAA record | Like an A record, but for IPv6 addresses — the newer, longer format of IP addresses. |
| Accreditation | The process that authorizes a company to sell domain names. Only ICANN-accredited registrars can sell domains. |
| Auth code | Also called EPP code, transfer code, or authorization code. A password-like string needed to transfer a domain to a new registrar. |
| Auto-renew | A setting that automatically renews your domain each year using a saved payment method. Always keep this on. |
| Cloudflare | A popular service that acts as a DNS provider, CDN, and security layer for websites. See Cloudflare basics for clients. |
| CNAME record | Canonical Name record. Points one domain name (or subdomain) to another domain name instead of an IP address. Often used for www or subdomains like mail.yoursite.com. |
| DNS | Domain Name System. The internet's address book — translates human-readable domain names into IP addresses. See What is DNS?. |
| DNS propagation | The time it takes for a DNS change to spread across all servers worldwide. Can take minutes to 48 hours. See DNS propagation. |
| DNS record | An instruction in your domain's DNS settings. Different record types control different things (where the site points, where email goes, etc.). |
| DNS zone | The collection of all DNS records for a domain. Managed in your DNS provider's dashboard. |
| Domain | The human-readable address for your website, e.g. yourcompany.com. See What is a domain name?. |
| Domain locking | A security feature that prevents unauthorized transfers. Most domains should be locked except when actively transferring. |
| Domain privacy | A service that hides your personal contact information from the public WHOIS database. Also called WHOIS privacy or privacy protection. |
| Domain registrar | The company where you registered your domain — GoDaddy, Namecheap, Google Domains, etc. |
D–G
| Term | Plain-English definition |
|---|---|
| DKIM | DomainKeys Identified Mail. A DNS record that digitally signs outgoing emails so receiving servers can verify they're genuine. See DKIM records, explained. |
| DMARC | Domain-based Message Authentication, Reporting & Conformance. A DNS policy that tells email servers what to do with messages that fail SPF or DKIM checks. See DMARC records, explained. |
| Domain extension | The suffix at the end of a domain — .com, .org, .net, .io, .co.uk. Also called a TLD (Top-Level Domain). |
| Domain transfer | Moving a domain from one registrar to another. Requires the auth code and unlocking the domain. |
| Expired domain | A domain whose registration has lapsed. It may go into a grace period, then become available for others to buy. |
| Forwarding | Redirecting a domain or URL to another address. www.yoursite.com forwarding to yoursite.com is a common example. |
| Glue record | A special DNS record needed when your nameservers are within the same domain (e.g. ns1.yoursite.com). Prevents a chicken-and-egg lookup problem. |
| Grace period | A window after a domain expires (usually 30–45 days) during which you can still renew it before it's released publicly. |
H–N
| Term | Plain-English definition |
|---|---|
| ICANN | Internet Corporation for Assigned Names and Numbers. The non-profit that oversees domain registration worldwide. |
| IP address | A unique numerical address for a server. DNS translates your domain name into this address so browsers know where to go. |
| MX record | Mail Exchange record. Tells email servers where to deliver email for your domain — points to your email provider. |
| Nameserver | A server that holds the DNS records for a domain. When you "point your domain" to a host, you usually update the nameservers. |
| Nameserver delegation | Handing control of your domain's DNS to a specific nameserver — usually your hosting provider's or Cloudflare's. |
| NS record | The DNS record type that lists your domain's nameservers. |
P–R
| Term | Plain-English definition |
|---|---|
| Parked domain | A registered domain that doesn't point to an active website yet. Often shows a placeholder page. |
| Pointing | Changing DNS records so your domain directs visitors to a new server or service. |
| Propagation | See DNS propagation above. The delay while changes spread worldwide. |
| Redirect | Automatically sending visitors from one URL to another. A 301 redirect is permanent; a 302 is temporary. |
| Registrant | The person or company legally registered as the domain owner. |
| Registrar | See Domain registrar. The company that manages your domain registration. |
| Registry | The organization that manages a top-level domain (TLD) like .com, .org, or .uk. Registrars sell to customers on the registry's behalf. |
| Renewal | Paying to extend your domain registration for another year (or more). |
| Root domain | The core domain without any subdomain prefix — yourcompany.com rather than www.yourcompany.com. |
S–Z
| Term | Plain-English definition |
|---|---|
| SOA record | Start of Authority. Technical record that defines the primary nameserver and administrative details for a DNS zone. You rarely need to touch this. |
| SPF record | Sender Policy Framework. A DNS TXT record that lists which servers are allowed to send email on behalf of your domain. See SPF records, explained. |
| SSL/TLS | The encryption layer that makes HTTPS work. Your hosting provider usually sets this up; it shows as a padlock in the browser. |
| Subdomain | A prefix added before your main domain — blog.yoursite.com, shop.yoursite.com. See Subdomains explained. |
| TLD | Top-Level Domain. The last part of a domain name — .com, .org, .net, .io, .shop, .co.uk. |
| TTL | Time To Live. How long (in seconds) DNS servers around the world cache a DNS record before re-checking it. Lower = faster updates; higher = less load. |
| TXT record | A flexible DNS record that can hold any text value. Used for domain verification, SPF, DKIM, and more. |
| Transfer | See Domain transfer. Moving a domain between registrars. |
| WHOIS | A public database of domain registration information — who owns a domain, when it expires, the registrar, nameservers. Domain privacy hides your personal details from WHOIS. |
| www | A subdomain prefix (www.yoursite.com). Short for World Wide Web. Most modern sites work with or without it. See www vs non-www. |
| Zone file | The text file containing all DNS records for a domain. You interact with these records through your registrar or DNS provider's dashboard. |
Common questions
Related guides
- What is DNS?
- DNS records explained (A, CNAME, MX, TXT)
- Email DNS records (MX, SPF, DKIM, DMARC)
- Domain & DNS terms, explained simply
- Web basics: terms A–Z
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