TLDlive

Domain Name Glossary: Registry, DNS and Lifecycle Terms

Short, precise definitions of the terms you meet when registering, monitoring, buying or losing a domain, arranged alphabetically so you can jump straight to the one you need.

Domain vocabulary mixes three worlds: DNS engineering, the contractual structure around ICANN, and the aftermarket. The same event can carry a different name in each. This glossary defines each term in a sentence or two and points out where a term is easy to confuse with a neighbour. Where a number depends on the registry or registrar, the entry says so instead of guessing.

Terms A to C

A record

A DNS record that maps a hostname to an IPv4 address. A domain can have several A records for the same name, and resolvers rotate or choose among them.

AAAA record

The IPv6 counterpart of the A record. A site reachable over both protocols publishes both.

Abuse contact

The email and phone a registrar must publish so third parties can report phishing, malware or illegal content on domains it sponsors. Reports to it are often the fastest route to a takedown.

Add grace period

A short window after a new registration during which a registrar can delete the domain and get its fee back. It was the mechanism behind domain tasting and is now limited by ICANN's add grace period limits, which let registries charge for excess deletions.

Aftermarket

The secondary market where already-registered domains are bought and sold between parties, through marketplaces, brokers, auctions or direct offers, as opposed to first-time registration.

Anycast

A routing technique where many servers in different places share one IP address and the network delivers each query to a nearby one. Large DNS providers and the root servers use it for speed and resilience.

Appraisal

An estimate of a domain's resale value. Automated appraisals are rough; real value is whatever a specific buyer will pay. Why they diverge is a recurring theme in domain investing.

Auction (domain)

A time-limited sale where bidders compete for a name, either an expiry auction run by a registrar for a lapsed domain or an aftermarket auction for a name an owner chose to sell.

Auth code (EPP code)

A secret string issued by the current registrar that the receiving registrar needs to start a transfer. It is also called an authorization code or transfer key. Treat it like a password.

Authoritative nameserver

A nameserver that holds the actual records for a zone and answers for it definitively, as opposed to a recursive resolver that only caches answers.

Auto-renew

A registrar setting that charges the saved payment method and extends the registration shortly before expiry. It fails silently when the card is declined or expired.

Auto-renew grace period

The stretch after expiry during which the domain can still be renewed at the normal price. ICANN describes it as an optional period of 1 to 45 days that registrars may offer, so the length is the registrar's choice and may be zero, and many website owners see their site go offline during it.

AXFR

A DNS operation that transfers a whole zone from one server to another. Most TLD registries do not offer it publicly; zone data for gTLDs is distributed through CZDS instead.

Backorder

An advance request to catch a domain the moment it is released after deletion. Several parties can backorder the same name, which usually leads to a private auction. Details are in drop catching and backorders.

Bulk registration

Registering many domains in one operation, usually through a registrar's list tool or API. Legitimate for portfolios and brand defence; also the pattern behind large phishing and spam campaigns, which is why bulk-registered names get extra scrutiny.

cctld

A country code top-level domain, such as .de or .vn, tied to a country or territory and a two-letter code. Each is run under local rules that can differ sharply from gTLD rules. See gTLD vs ccTLD vs new gTLD.

clientDeleteProhibited

An EPP status set by the registrar that blocks deletion of the domain until it is removed. A basic protection against accidental or hijack-driven deletion.

clientHold

An EPP status set by the registrar that removes the domain from the zone, so it stops resolving, although it is still registered. Common after non-payment or a verification failure.

clientRenewProhibited

A registrar-set status that prevents renewal commands. Rare, and often a sign of a dispute or a registrar-side restriction.

clientTransferProhibited

The status behind a registrar "transfer lock". While present, the domain cannot be moved to another registrar. Remove it only when you intend to transfer.

clientUpdateProhibited

A registrar-set status that blocks changes to contacts and nameservers on the registry record until it is removed.

CNAME record

A DNS record that makes one name an alias for another. It cannot sit at the zone apex alongside other records, which is why providers invented ALIAS or flattening features.

Cybersquatting

Registering a name that matches or imitates someone's trademark in bad faith, usually to resell it or profit from the confusion. It is the core offence in the UDRP and the US ACPA. Related reading: typosquatting and lookalike domains.

CZDS

The Centralized Zone Data Service run by ICANN, through which approved users request daily zone file access from participating gTLD registries. How it works is covered in zone files and ICANN CZDS.

Terms D to F

Delegation

The act of a parent zone pointing to a child zone's nameservers using NS records. A domain is "delegated" when its TLD zone lists nameservers for it.

DNS

The Domain Name System, the distributed database that translates names into addresses and other data. See DNS nameservers and providers for how hosting choices affect it.

DNSKEY record

A DNS record that publishes a zone's public signing key. Validating resolvers use it to check the signatures on the zone's other records.

DNSSEC

Domain Name System Security Extensions, a set of signatures that let a resolver verify DNS answers were not altered. It protects integrity, not privacy, and needs a matching DS record at the parent.

Domain tasting

The former practice of registering large numbers of names, keeping them during the add grace period to measure traffic, and deleting the unprofitable ones for a refund. Policy changes made it uneconomic.

Dot-brand

A TLD operated by a single company for its own use, such as a brand name as the extension. Not open for public registration.

Drop catching

Sending registration requests at very high speed at the moment a deleted domain becomes available again, to win the name before competitors. Specialist services do this on behalf of customers.

Dropped domain

A domain that has completed deletion and is available to register again. In everyday speech people also use it for any expiring name; the lifecycle guide separates the stages.

DS record

Delegation Signer record, a hash of a child zone's key published in the parent zone. It is the link that makes the DNSSEC chain of trust work; a wrong DS record can make the domain fail to resolve for validating resolvers.

EPP

The Extensible Provisioning Protocol (RFC 5730), the XML-based protocol registrars use to create, update, renew, transfer and delete domains at a registry.

EPP status codes

Flags on a registry record that describe the state of a domain and what operations are blocked. Names starting with client are set by the registrar, those starting with server by the registry. Common ones have their own entries in this glossary: ok, clientHold, serverHold, pendingDelete, redemptionPeriod.

ERRP

The Expired Registration Recovery Policy, an ICANN rule for registrars of gTLDs. It requires at least two renewal notices before expiry and another if the name is still not renewed or deleted five days after expiry, lets the holder renew the expired name, requires fee disclosure, and requires gTLD registries (sponsored ones excepted) to offer a 30-day redemption period.

Expired domain

A domain whose registration term ended without renewal. It is not necessarily available: it may sit in grace, redemption or pending delete for weeks first. Browse expired domain lists for names that have dropped out of the zone.

FQDN

Fully qualified domain name, a hostname written in full from the leaf to the root, ending in a dot in strict notation: www.example.com.

Terms G to L

GDPR redaction

Since 2018, most registrars and registries hide personal registrant data in public WHOIS output, replacing it with a redacted placeholder or a contact form.

Glue record

An A or AAAA record for a nameserver published in the parent zone, needed when the nameserver's name sits inside the domain it serves, for example ns1.example.com serving example.com. Without glue, resolution would loop.

gTLD

A generic top-level domain, not tied to a country: legacy ones such as .com and .org, and hundreds of new gTLDs introduced from 2013 onward.

Grace period

A generic term for any window after an event in which a mistake can be undone. The add grace period follows registration; the auto-renew grace period follows expiry; the redemption grace period follows deletion.

Hold (serverHold)

An EPP status set by the registry that removes the domain from the zone. It is applied for legal orders, abuse findings or billing problems, and only the registry can lift it.

HSTS preload

A list built into browsers of domains that must only be reached over HTTPS. Submitting a domain is easy; getting out of the list can take months, so confirm every subdomain supports HTTPS first. Some TLDs, such as .app and .dev, are preloaded as a whole.

IANA

The Internet Assigned Numbers Authority, a function operated by ICANN that maintains the root zone and the database of every TLD with its operator and delegation details.

ICANN

The Internet Corporation for Assigned Names and Numbers, the nonprofit that coordinates the DNS root and sets policy for gTLDs through contracts with registries and registrars.

IDN

An internationalized domain name containing non-ASCII characters such as accented letters or non-Latin scripts. Stored in DNS as punycode. Lookalike characters create spoofing risks; see IDNs, punycode and homographs.

Inactive (EPP status)

A status meaning a domain is registered but has no nameservers, so it is not in the zone and does not resolve.

Terms M to P

Mail exchanger (MX record)

A DNS record naming the server that accepts email for a domain, with a priority number. Losing a domain to expiry also silently breaks its mail.

Nameserver

A server that answers DNS queries. A domain lists at least two in its NS records for redundancy.

NRD

A newly registered domain, usually meaning one registered in the last days or weeks. Security teams track NRDs because a high share of malicious domains are used soon after registration. Daily lists are described in newly registered domains.

NS record

The DNS record that names the authoritative nameservers for a zone. At the TLD level, NS records are the delegation itself.

ok (EPP status)

The default status of an active domain with no pending operations and no locks. It is shown only when nothing else applies.

Parked domain

A registered domain with no real site, showing an ad page or a sale notice. Parking by itself says nothing about whether the owner will sell.

Pending delete

The last stage before release, lasting about five days for gTLDs, during which the domain can no longer be recovered by the owner. It then drops and becomes available. The EPP status is pendingDelete.

pendingTransfer

An EPP status showing that a transfer request is waiting for approval or for the response window to expire.

Premium domain

A name that a registry prices above standard registration, either at first sale or permanently, including on renewal. Always check the renewal price before buying.

Punycode

The ASCII encoding (RFC 3492) of an internationalized label. It appears as the prefix xn-- followed by encoded text, so xn--bcher-kva.example corresponds to bücher.example.

Terms Q to S

RAA

The Registrar Accreditation Agreement between ICANN and each accredited registrar. It sets obligations such as abuse handling, data escrow and renewal reminders.

RDAP

The Registration Data Access Protocol, a JSON-over-HTTPS replacement for WHOIS with standard fields, structured errors and access control. Compare them in WHOIS vs RDAP.

Recursive resolver

A server that follows delegations from the root downward to find an answer for a client and caches the result. Your ISP, and public services, run them.

Redemption grace period

A period of 30 days for most gTLDs after a registrar deletes a domain at the registry, during which the original registrant can still recover it by paying a restore fee in addition to renewal. The EPP status is redemptionPeriod.

redemptionPeriod

The EPP status shown while a domain is in the redemption grace period. The name is usually removed from the zone while this status is active.

Registrant

The person or organisation that holds the rights to a domain registration, as opposed to the registrar that processes it or a reseller or web agency that merely manages it.

Registrar

An ICANN-accredited company, or a reseller of one, that sells domain registrations to the public and communicates with the registry on your behalf.

Registry

The organisation that operates a TLD, maintains its authoritative database and publishes its zone, for example Verisign for .com.

Registry lock

A stronger lock applied at the registry, which requires out-of-band verification before changes such as nameserver updates or transfers. Used by high-value domains.

Renewal price

What it costs to extend a registration, which for many TLDs is higher than the first-year promotional price. Always read it before registering.

Reserved name

A label a registry or ICANN has withheld from general registration, such as technical names or names kept for the operator's own use. A reserved name cannot be registered through ordinary channels.

Root zone

The top of the DNS hierarchy, listing every TLD and its nameservers. Maintained under the IANA function and served by the root server system.

RRP

The Registry Registrar Protocol (RFC 2832), the early protocol used between registrars and the shared .com registry before EPP replaced it.

SLD

Second-level domain, the label directly left of the TLD. In example.com, example is the SLD. In example.co.uk people often loosely use the term for the part before .co.uk.

SOA record

Start of Authority, a record at the top of every zone that gives the primary nameserver, an administrator contact, and a serial number and timers used for zone transfers.

Sponsoring registrar

The registrar currently recorded at the registry as responsible for a domain. A transfer changes it.

Subdomain

A name created under a domain you control, such as blog.example.com. It needs no registration and costs nothing.

Sunrise period

The first phase of a new TLD launch, during which holders of validated trademarks may register matching names before general availability. It is followed by a claims period during which applicants are warned about conflicting marks.

Terms T to Z

TLD

Top-level domain, the last label in a name, such as com, uk or shop. IANA lists them in the root zone database.

TMCH

The Trademark Clearinghouse, a central database of verified trademarks used for sunrise registrations and for claims notices during new gTLD launches.

Transfer lock

A setting in the registrar panel that applies clientTransferProhibited. Registrations are also commonly blocked from transfer for the first 60 days after creation or a previous transfer. Registrars may also refuse a transfer within 60 days of a domain's creation date or of a previous transfer. ICANN's Transfer Policy allows this (sections I.A.3.7.5 and I.A.3.7.6) rather than requiring it, and many registrars apply it to every domain; a separate 60-day lock can follow a change of registrant unless the holder opted out. ICANN's Board adopted the Transfer Policy Review recommendations on 7 June 2026 and directed their implementation, and the working group proposed a single 30-day restriction, but we found no published effective date, so 60 days remains the working assumption.

TTL

Time to live, the number of seconds a DNS answer may be cached. Lower it before a migration so changes take effect quickly.

UDRP

The Uniform Domain-Name Dispute-Resolution Policy, the ICANN procedure for resolving cybersquatting disputes. A complainant must show the name is confusingly similar to its mark, the holder lacks rights or legitimate interests, and registration and use were in bad faith.

URS

Uniform Rapid Suspension, a faster and cheaper dispute procedure used mainly in new gTLDs; check that a given extension's registry has adopted it. The outcome is suspension of the name, not transfer.

WHOIS

The older text query protocol (RFC 3912, port 43) for looking up who is registered for a domain and when it expires. Many fields are now redacted, and the registration data is shifting to RDAP: since 28 January 2025 ICANN no longer requires gTLD registries and registrars to run WHOIS, with .com, .name and .post named as exceptions on ICANN's RDAP FAQ.

Zone

The portion of the DNS namespace managed as a unit by one operator, stored in a zone file.

Zone file

A text file listing the records in a zone. A TLD zone file lists each delegated domain and its nameservers, which is why it reveals new and removed delegations but not owners or prices.

Sources

Frequently asked questions

What is the difference between a registrar and a registry?

The registry operates the TLD and keeps the master database for it, for example Verisign for .com. The registrar is the retailer that sells registrations to you and submits them to the registry over EPP.

What is the difference between the auto-renew grace period and the redemption grace period?

The auto-renew grace period comes first, right after expiry, and lets the owner renew at the normal price if the registrar allows it. The redemption grace period comes after deletion and costs a restore fee on top of renewal. Both are described in the domain lifecycle guide.

Which EPP status codes make a domain stop resolving?

clientHold and serverHold explicitly remove the name from the zone. redemptionPeriod and pendingDelete typically do too, and inactive means no nameservers are set.

Is a domain that vanishes from a zone file always deleted?

No. Removal from a zone can mean deletion, but it can also mean a hold, a suspension or removed nameservers. A zone file does not show which, so check WHOIS or RDAP status.

Does WHOIS still show the owner's name?

Usually not for individuals. Since 2018, registrars and registries mostly redact personal data, and the remaining fields such as dates, status and nameservers are what you can rely on.

Why does a punycode name start with xn--?

The prefix marks a label as an encoded internationalized name. Browsers decode it for display, but the DNS only stores the ASCII form.