Glossary
Domain glossary
Plain-English answers to 27 domain questions: how a domain expires and drops, how DNS and email security work, and the words used when you look for, buy or protect a name.
The basics
- Domain name
- A domain name is the human-readable address of a website or email service, such as example.com, that points to servers through the DNS.
- TLD (top-level domain)
- A top-level domain, or TLD, is the last part of a domain name, such as .com, .org or .uk. It is the extension that follows the final dot.
- Registrar
- A registrar is a company accredited to sell domain names and manage them for you, such as GoDaddy or Namecheap. You register and renew a domain through one.
- Registry
- A registry is the organisation that runs one top-level domain and keeps the master database of its names. Verisign is the registry for .com.
When a domain expires and drops
- Expired domain
- An expired domain is a name whose registration period ended without being renewed. It is not released at once: it passes through several grace periods first.
- Auto-renew grace period
- The auto-renew grace period is the time just after a domain expires, typically up to about 45 days, when the owner can still renew it at the normal price.
- Redemption period
- The redemption period is a stage of about 30 days after the grace period when a deleted domain can still be restored by its owner, for an extra fee.
- Pending delete
- Pending delete is the last stage before a domain is released: a period of about five days when the owner can no longer restore it and it is about to be deleted.
- Domain drop
- A domain drop is the moment an expired name is finally deleted by the registry and becomes available for anyone to register again.
- Backorder (drop catching)
- A backorder is a request to a service to try to register a domain the instant it is deleted. Drop catching is the practice of doing this at scale.
DNS, email and security
- DNS (Domain Name System)
- DNS is the internet's phone book: it turns a domain name into the addresses and settings that browsers and mail servers need to reach it.
- Nameserver
- A nameserver is a server that holds a domain's DNS records and answers questions about it. A domain lists at least two so one can fail.
- DNS provider
- A DNS provider is the company that runs the nameservers for a domain. It is often, but not always, the registrar or the web host.
- SPF record
- An SPF record is a DNS entry that lists the servers allowed to send email for a domain, so receivers can spot mail that is faked.
- DKIM
- DKIM adds a digital signature to outgoing email, checked against a public key published in the sender's DNS, so receivers can tell the message was not altered.
- DMARC
- DMARC is a DNS policy that tells receiving mail servers what to do with email that fails SPF or DKIM checks, and where to send reports about it.
- Transfer lock
- A transfer lock is a setting at the registrar that stops a domain from being moved to another registrar without the owner's approval.
Kinds of names
- Domain hack
- A domain hack is a name where the extension completes the word, so the whole address reads as one word or phrase, such as short.ly or brand.ai.
- Brandable domain
- A brandable domain is a short, easy-to-say name that works as a brand even though it may not describe what the business does, such as Google or Spotify.
- IDN (internationalised domain name)
- An internationalised domain name, or IDN, is a domain written with letters beyond the basic Latin alphabet, such as accented letters or Chinese characters.
- Typosquatting (lookalike domains)
- Typosquatting is registering a misspelling or lookalike of a well-known name, such as gooogle.com, to catch visitors who mistype or to imitate the brand.
Buying and selling
- Domain appraisal
- A domain appraisal is an estimate of how valuable a domain name is. Automatic appraisals are rough guides at best, because real value depends on a buyer.
- Domain aftermarket
- The domain aftermarket is the resale market for names that are already registered: marketplaces, brokers, auctions and direct sales between owners.
Lookups and data
- Zone file
- A zone file is the registry's list of every domain in an extension that has nameservers, with those nameservers. The .com zone has well over 160 million names.
- RDAP
- RDAP, the Registration Data Access Protocol, is the standard way to look up whether a domain is registered and its status. It replaced WHOIS.
- WHOIS
- WHOIS is the older lookup service that shows who registered a domain and when. Since 2018 much of the personal data it showed is hidden, and RDAP replaces it.
- Domain blocklist
- A domain blocklist is a list of domain names reported for spam, phishing or malware, used by mail and security systems to block or flag them.
Check a name yourself
The tools put these words to work: check whether a name is free, the Drop Calendar for names about to be released, and the Domain Health Check for DNS and email security.