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General

Domain and DNS Glossary

Updated

Domain jargon is mostly historical accident. The words below are the ones you will actually run into — in your client area, in a registrar’s control panel, or in an email telling you something needs your attention.

They are in alphabetical order. Nothing here assumes you have read anything else.

A record

The DNS record that points a name at an IPv4 address, which is what makes a website load. AAAA is the same idea for the newer IPv6 addresses, and plenty of sites have both. Your hosting provider tells you which address to use. More detail in DNS records explained.

Auth code

The password that authorises moving a domain to a different registrar. Also called an EPP code, a transfer key, or an authorization code — four names, one thing. You request it from the registrar you are leaving and hand it to the one you are joining. Codes can expire, so get yours when you are ready to start. See how to transfer a domain.

Auto-renew

A setting that renews your domain automatically before it expires. It is the single most effective protection against losing a name, because the alternative is remembering a date once a year. On by default for domains registered with us, and switchable in your client area.

ccTLD

A country-code top-level domain — two letters tied to a country or territory, like .uk, .de, or .au. Some are open to anyone in the world, some require a local presence, and each is governed by its own country’s rules rather than by ICANN. Every extension’s page in the directory says which applies.

CNAME

A DNS record that points one name at another name rather than at an address. Useful when a provider gives you a hostname to aim at instead of a fixed IP. A CNAME cannot sit on the bare root of your domain — that needs an A record, or your DNS host’s ALIAS equivalent.

DNS

The Domain Name System: the internet’s address book. It translates names people can remember into the addresses machines actually use. Everything below about records, nameservers, and TTL is a part of how it does that.

DNS record

A single instruction in your domain’s DNS, with a type that says what it is for — A for a web server, MX for mail, TXT for verification. Together they make up your zone. DNS management is free on every domain registered with us.

Domain name

The name itself — example.com. Made of a label you choose (example) and an extension you pick from what is available (.com). You do not buy it outright; you hold the exclusive right to use it for as long as you keep renewing.

Expiry

The date your registration runs out. It is not a cliff: most extensions give you a grace period to renew at the normal price, then a redemption period at a much higher one, then the name is released. What happens when a domain expires walks through the whole timeline.

Glue record

An address published at the registry for a nameserver that lives inside the domain it serves. Without it the lookup is circular: to find example.com you must ask ns1.example.com, which you cannot find without first finding example.com. Glue breaks the loop. You only meet this if you run your own nameservers.

gTLD

A generic top-level domain — the extensions not tied to a country. The originals (.com, .net, .org) plus the several hundred newer ones (.app, .shop, .tech). These are the extensions ICANN oversees directly, which is why gTLD rules on transfers and expiry are consistent across registrars.

ICANN

The organisation that coordinates the domain name system globally: it accredits registrars, sets the rules gTLD registries and registrars must follow, and publishes what you are entitled to as a registrant. Its registrant rights page is worth a read if a registrar ever tells you something you doubt.

IDN

An internationalised domain name — one containing characters outside basic ASCII, like café.com or a name in Arabic or Devanagari. Behind the scenes these are encoded into an ASCII form beginning xn--, which is why an IDN sometimes appears as an unreadable string in technical output.

MX record

The DNS record that says where email for your domain should be delivered. If your mail stops working after a DNS change, this is almost always the record that went missing. Note your MX records before changing nameservers — see DNS records explained.

Nameserver

A server that answers DNS questions about your domain. Your domain points at a set of them (usually two to four), and whoever runs those nameservers controls every DNS answer for the name. Changing nameservers replaces your entire zone — every record, MX included — which is why it is the one change worth planning.

Propagation

The delay between changing a DNS record and the whole internet seeing the change. It is not really a spreading process; it is caches expiring, one at a time, governed by the record’s TTL. Usually 15 to 60 minutes. Occasionally up to 48 hours, because some providers cache for longer than they were asked to.

Registrant

You — the person or organisation a domain is registered to. The registrant contact in the WHOIS record is who a registry treats as the owner, which is why keeping that email address current matters more than it looks. Approval emails for transfers go there.

Registrar

The company you buy and manage a domain through, accredited to write records into a registry on your behalf. We are a reseller working through ICANN-accredited registrars; your registration is real and portable either way, and you can transfer it out whenever you like.

Registrar lock

A flag on your domain that blocks transfers until you switch it off. It exists to stop somebody moving your name without permission, so it is on by default and slightly buried by design. You turn it off yourself at your current registrar when you genuinely do want to move.

Registry

The operator of a single extension, holding the master list of every domain under it. Verisign runs .com; Public Interest Registry runs .org; each ccTLD has its own. Registries set the price floor, the eligibility rules, and the expiry timeline for their extension — which is why those differ so much between extensions.

Redemption period

Roughly 30 days after an expired domain is removed from the zone, during which only you can recover it — at a redemption fee well above a normal renewal. Your site and email are already down by this point. After it ends, the name is deleted and anyone may register it.

Root zone

The top of the DNS hierarchy: the authoritative list of every extension that exists, published by IANA. If an extension leaves the root zone it stops resolving worldwide. We remove withdrawn extensions from our catalogue automatically for exactly that reason.

Second-level domain

A registrable namespace one level below an extension — co.uk, com.au, co.nz. To you it behaves like any other extension: you register yourname.co.uk the same way you would register yourname.com. There are 232 of them in our directory, alongside the top-level ones.

SSL certificate

The credential that lets a site be served over HTTPS, encrypting traffic between a visitor and your server and removing the “Not secure” warning browsers show without it. DV verifies you control the domain, OV additionally verifies your organisation, and a wildcard covers all your subdomains at once. See SSL certificates; a free one is included with every hosting plan.

Subdomain

A name below your domain — blog.example.com, shop.example.com. You create as many as you like from your DNS at no cost; they are not separate registrations and there is nothing to buy. Only the domain itself is registered.

TLD

Top-level domain: the part after the final dot. .com, .uk, .tech. Often just called the extension. Our directory covers 1,669 of them and their second-level namespaces, with eligibility rules and pricing for each.

TTL

Time To Live, in seconds: how long other servers may cache a DNS answer before checking again. A TTL of 3600 means an old value can survive an hour after you change it. Lower the TTL a day before a planned migration and the cutover happens in minutes rather than hours.

TXT record

A DNS record holding plain text, used mostly to prove you control the domain. Verification strings from Microsoft or Google are TXT records, and so are SPF, DKIM, and DMARC — the three that stop your legitimate email being treated as spam.

WHOIS

The public record of who registered a domain, when, through which registrar, and when it expires. Increasingly redacted for privacy reasons, but the registrar, dates, and status flags remain visible — which is what makes it useful for diagnosing a stalled transfer.

WHOIS privacy

A service replacing your personal contact details in the public WHOIS record with a forwarding address, keeping your name, home address, and phone number out of a database anyone can query. Free with us on every extension whose registry permits it. Turn it off temporarily during a transfer, so the approval email reaches you.

Zone

The complete set of DNS records for your domain. “Editing your zone” and “editing your DNS records” mean the same thing. Switching nameservers hands the zone to a different provider, which is why the old records do not come along unless you recreate them.

Still stuck on a word?

If something in an email or a control panel does not match anything here, that is worth telling us — it usually means a provider has invented its own name for one of the above. Send us a message or open a ticket and we will translate it.

Frequently asked questions

What is the difference between a registrar and a registry?
A registry runs a single extension and holds the master list of every domain under it — Verisign runs .com, for example. A registrar is the company you actually buy from, which is accredited to write records into that registry on your behalf. You deal with a registrar; the registry is who your registrar talks to.
What is the difference between a domain and a nameserver?
A domain is the name itself. Nameservers are the servers that answer questions about that name — where its website lives, where its email goes. Changing your domain's nameservers hands the whole set of answers to a different provider, which is why it replaces every DNS record at once.
What does TTL mean?
Time To Live: how many seconds other servers on the internet are allowed to remember a DNS answer before asking again. A record with a TTL of 3600 can serve its old value for up to an hour after you change it. Lowering the TTL a day before a planned change makes the change take effect faster.
What is an auth code?
A short password that proves you are entitled to move a domain to another registrar. Depending on who you ask it may be called an EPP code, a transfer key, or an authorization code — they are all the same thing. You get it from your current registrar and give it to your new one.
What is the redemption period?
A roughly 30-day window after a domain has expired and been deleted from the zone, during which only the original registrant can recover it — usually for a substantial redemption fee on top of the renewal. It is the last chance before the name is released for anyone to register.
Do I need to understand all of this to own a domain?
No. Most people never touch anything beyond renewing on time. This page exists so that when a support article or a registrar's control panel uses one of these words, you can look it up rather than guess. Our team will make any of these changes for you if you would rather not.