Domain industry glossary

Plain-language definitions of the terms used in our reviews and methodology. Each entry has a stable anchor so we can link to it from other pages (e.g. methodology) and so search engines and AI agents can extract definitions cleanly.

Last updated 2026-08-19Prices checked monthly1 of 9 scored reviews with published testing notes6 registrars with primary-source pricingTransparent methodology

A

A record#: A DNS record mapping a name to an IPv4 address — the most common way to point a domain at a server.
AAAA record#: A DNS record mapping a name to an IPv6 address (the modern, larger address space).
Add Grace Period (AGP)Add Grace Period#: A short window (typically 5 days) after a new registration in which the registrar can delete it for a full registry refund — historically abused for 'domain tasting'.
Aftermarket#: The secondary market where already-registered domains are bought and sold between parties, often at prices far above registration cost.
ALIAS / ANAME record#: A registrar-specific record type that mimics a CNAME at the zone apex, letting a bare domain point at a hostname. Support varies by provider.
Anycast DNS#: A technique where the same nameserver IP is announced from many locations, so queries hit the nearest one — faster and more resilient DNS.
At-cost pricing#: Selling domains at the wholesale registry fee plus the mandatory ICANN fee, with no registrar profit margin — the cheapest possible long-term price.
Authoritative DNS#: The DNS server that holds the real records for a zone and gives definitive answers, as opposed to a caching resolver that just relays them.
Auto-renew#: A default setting where the registrar charges your card to renew a domain automatically before it expires, preventing accidental loss.
Auto-renew grace period#: The 45-day window after an expiration during which the registrar can return an auto-renewed domain to the registry for a refund. This is what enables most registrars to offer a 'free recovery within 45 days' policy on expired domains.

B

Back-end registry#: The technical provider that operates a TLD's registry systems on behalf of the TLD owner. Many small gTLD owners outsource operations to a shared back-end provider.
Backorder#: Paying a service in advance to attempt to register a specific domain the moment it becomes available, without guarantee of success.
Brand TLD (.brand)#: A top-level domain owned and operated by a single company for its own exclusive use, applied for through ICANN's new-gTLD program.
Bulk transfer#: Moving many domains between registrars at once, either via the registrars' bulk tools or, for whole portfolios, an ICANN bulk-transfer procedure.

C

CAA recordCertification Authority Authorization record#: A DNS record that lists which certificate authorities are allowed to issue TLS certificates for a domain, reducing mis-issuance risk.
Catch-all email#: A forwarding rule that accepts mail to any address at your domain and routes it to one inbox.
ccTLDcountry-code top-level domain#: A two-letter TLD assigned to a country or territory, such as .uk, .de, .ca, .il, .ai. ccTLDs are governed by their country's chosen registry and may have local-presence rules, language requirements, or restricted second-level domains.
Chain of trust#: The DNSSEC hierarchy where each level cryptographically vouches for the one below — root signs the TLD, the TLD signs your domain — so a resolver can verify answers weren't tampered with.
Change of registrant (COR)Change of Registrant#: A material change to the registered owner's identity. Under ICANN policy it can trigger a fresh 60-day transfer lock, which many registrars let you opt out of.
CNAME recordCanonical Name record#: A DNS record that aliases one name to another name, so both resolve to the same place. Cannot be used at the zone apex (the bare domain).
Cybersquatting#: Registering a domain that matches someone else's trademark in bad faith, usually to sell it to them or divert traffic.

D

Delegation#: The act of a parent zone pointing a domain or subdomain to its own nameservers via NS records — how authority is handed down the DNS tree.
DNSDomain Name System#: The hierarchical naming system that translates human-readable domain names into IP addresses and other resource records. A registrar's DNS quality is judged on supported record types, propagation behavior, and reliability of its authoritative servers.
DNS cache#: Stored DNS answers held by resolvers and operating systems for the record's TTL, so repeat lookups are fast — and why changes take time to appear everywhere.
DNS propagation#: The informal term for the time it takes a DNS change to be seen everywhere, governed by record TTLs and cache expiry — not an actual global 'push'.
DNS record#: An entry in a domain's zone that tells the internet how to route different kinds of traffic — web, email, verification. Managed at your DNS provider.
DNSSECDomain Name System Security Extensions#: A set of extensions that cryptographically sign DNS records so resolvers can verify they haven't been tampered with. Registries publish DS records into the parent zone; the registrar typically provides a UI to upload your DS record.
Domain investing (domaining)#: Registering or buying domains to resell at a profit, betting on future demand for particular names.
Domain lifecycle#: The stages a domain moves through: available → registered → (if not renewed) expired → auto-renew grace → redemption → pending delete → dropped back to available.
Domain parking#: Pointing an unused domain at a placeholder page, often showing ads, to earn small revenue or hold it for later sale.
Domains By Proxy, LLC#: GoDaddy's WHOIS privacy company, which lists itself as the registrant in public records to keep the real owner's details private. Unrelated to Google Domains despite common co-searching.
Drop#: The moment an expired, unrecovered domain is deleted by the registry and becomes available for anyone to register again.
Drop-catching#: Using automated systems and many registrar connections to register a valuable domain the instant it drops, before ordinary users can.
DS recordDelegation Signer record#: Delegation Signer record — the fingerprint of your DNSSEC key that you publish at the registry (via your registrar) to link your signed zone into the chain of trust.
Dynamic DNS (DDNS)#: A service that automatically updates a DNS record when a device's IP changes — useful for home servers on residential connections.

E

Email forwarding#: A registrar feature that forwards mail sent to your domain to an existing inbox, without running a full mailbox — a cheap way to get you@yourdomain.
EPP authorization codeauth code, transfer code#: A short alphanumeric code generated by the current registrar that the new registrar requires to initiate a transfer. The registrant must request it from the losing registrar; it cannot be obtained any other way.
EPP status codesExtensible Provisioning Protocol status codes#: Standardized flags on a domain (visible in WHOIS/RDAP) that show its state — such as clientTransferProhibited (a lock) or pendingDelete.
Expiry date#: The date a registration ends. If not renewed, the domain enters the post-expiry lifecycle; it usually keeps working briefly during the grace period.

F

First-year price#: The often-discounted price to register a domain for its first year, which can be far below the renewal price. Judge long-term cost by renewal, not first-year.
FQDNFully Qualified Domain Name#: Fully qualified domain name — the complete, unambiguous name including every label up to the root, sometimes written with a trailing dot.

G

Gaining registrar#: The registrar you are transferring a domain to. It initiates the transfer using the authorization code.
GDPR redaction#: Since 2018, registries and registrars redact most personal data from public WHOIS/RDAP for individuals to comply with the EU's GDPR — so 'privacy' is now partly the default, not just a paid add-on.
General availability (GA)General Availability#: The phase when a TLD is open for anyone to register names first-come, first-served at standard prices.
Glue record#: An IP address record stored at the parent registry for a name server whose hostname falls under the same domain it serves. Used to break the chicken-and-egg lookup problem when ns1.example.com is the name server for example.com.
Grace period#: A window after expiry during which the original registrant can still renew at the normal price before the domain enters redemption.
gTLDgeneric top-level domain#: A TLD not tied to a country, such as .com, .org, .net, .app, .dev. Most gTLDs are policy-governed by ICANN and have published wholesale price agreements.

H

HTTPS / HSTS#: HTTPS is encrypted web traffic; HSTS is a policy that forces browsers to always use HTTPS for a site — and some TLDs (.dev, .app) enforce it for the whole zone.

I

IANAInternet Assigned Numbers Authority#: The function within ICANN that maintains the authoritative root zone file, the registry of all top-level domains, and global IP address allocation. The IANA root database lists the registry operator for every TLD.
ICANNInternet Corporation for Assigned Names and Numbers#: The non-profit organization that coordinates the assignment of domain names and IP addresses globally. ICANN accredits registrars, sets policy for generic top-level domains (gTLDs), and oversees the contractual relationships between registries and registrars.
ICANN fee#: A $0.18 USD per-year fee that ICANN charges registrars for each gTLD registration. It is itemized separately by some registrars (notably Cloudflare's at-cost pricing) and bundled into the headline price by others.
ICANN-accredited registrar#: A company that has signed ICANN's Registrar Accreditation Agreement and is authorized to register gTLD domains directly with the registries. Each has a unique IANA registrar ID.
IDNInternationalized Domain Name#: A domain containing non-ASCII characters (e.g. Cyrillic, Hebrew, Chinese). Implemented via Punycode encoding in the DNS layer (xn--prefixed labels). Not all TLDs support IDNs.
IETF / RFCInternet Engineering Task Force / Request for Comments#: The Internet Engineering Task Force writes the internet's technical standards as numbered RFC documents — including the ones defining DNS, EPP, and DNSSEC.
IPS tag#: The UK equivalent of a transfer authorization code: to move a .uk/.co.uk domain you set its IPS tag to the new registrar's tag rather than pasting an EPP code.

K

KSK / ZSKKey-Signing Key / Zone-Signing Key#: Key-Signing Key and Zone-Signing Key — the two DNSSEC keys. The KSK signs the keyset (and is referenced by the DS record); the ZSK signs the actual records.

L

Landrush#: A launch phase after sunrise where anyone can apply for premium or contested names in a new TLD, often by auction, before open registration.
Local presence#: A requirement (or optional service) that a domain have a contact or trustee based in the TLD's country. Some registrars sell a local-presence service to meet it.
Losing registrar#: The registrar you are transferring a domain away from. It must release the domain and can only refuse for specific ICANN-allowed reasons.

M

Markup#: The margin a registrar adds on top of the wholesale registry fee and the ICANN fee to set your retail price. At-cost registrars add little or none.
MX recordMail Exchange record#: A DNS record that tells the internet which mail servers accept email for a domain, with priority values.

N

Name servers#: The authoritative DNS servers a registrar configures at the registry to delegate a domain. Changing name servers points the domain to a different DNS provider (e.g. moving from your registrar's DNS to Cloudflare DNS) without transferring the domain itself.
Nameserver#: A server that answers DNS queries for a domain. Your registrar points the domain at nameservers, which then serve your records.
Nexus requirement#: A rule requiring the registrant to have a specific connection to a place or group — residency, citizenship, or a local business — to register a TLD.
NS recordName Server record#: A DNS record naming the authoritative nameservers for a domain or subdomain — the source of truth for its zone.

P

Pending delete#: The final ~5-day lifecycle stage after redemption, when the domain can no longer be recovered and is queued to drop back to available.
Premium domain#: A domain reserved by the registry (or a previous registrant) and sold at a higher-than-standard wholesale price. Each registrar surfaces premium prices differently; some registrars don't sell premium tiers at all.
Premium TLD / premium name#: A specific domain the registry itself prices above the standard rate (often permanently, including renewals) because it's short or valuable — separate from aftermarket resale.
Privacy / proxy service#: A service that replaces the registrant's real contact details in public WHOIS with the provider's own, shielding the owner's name, address, email, and phone.
Punycode#: An ASCII encoding (prefix 'xn--') that represents internationalized (non-Latin) domain names, since DNS itself only handles ASCII. Browsers show the readable Unicode form.

R

RDAPRegistration Data Access Protocol#: The structured JSON successor to WHOIS. ICANN required gTLD registries and registrars to support RDAP by 2019. RDAP supports standardized authentication, internationalized data, and machine-readable responses.
Recursive resolver#: The DNS server (run by your ISP or a public resolver like 1.1.1.1) that chases a query from the root down to the authoritative answer and caches it.
Redemption Grace Period (RGP)Redemption Grace Period#: The ~30-day stage after the grace period when a domain is held for possible recovery by the original registrant for a steep redemption fee, before pending delete.
Redemption period#: The 30-day window after a gTLD domain expires during which the registrant can recover it by paying a redemption fee (typically $80-$200). After redemption, the domain enters a pending-delete state for 5 days, then drops to the open market.
Registrant#: The person or organization that legally owns a domain registration. Contact details for the registrant are recorded in the registry's WHOIS database (subject to privacy redaction).
Registrar#: An ICANN-accredited (for gTLDs) or registry-accredited (for ccTLDs) company that sells domain registrations to end users on behalf of registries. Registrars handle billing, DNS configuration, WHOIS records, and transfers.
Registrar data escrow#: An ICANN requirement that registrars regularly deposit registrant data with a neutral third party, so registrations survive if a registrar fails.
Registrar lock#: A status flag (clientTransferProhibited) the registrar sets on a domain to block transfer requests until the registrant unlocks it. Helps prevent unauthorized transfers. Distinct from registry lock, which is set at the registry level for additional security.
Registrar of record#: The ICANN-accredited registrar officially responsible for a domain's registration — the entity a transfer moves the domain away from or into. A reseller's registrar of record is its accredited backend.
Registry#: The organization that operates a top-level domain and maintains the master database of all second-level registrations under it. Examples: Verisign operates .com and .net; Public Interest Registry operates .org; Identity Digital operates .io.
Registry fee (wholesale)#: The per-domain price the registry charges registrars, set by the registry contract. Your retail price is this fee plus the registrar's markup (and the ICANN fee for gTLDs).
Registry lock#: A higher-security lock applied at the registry, requiring out-of-band verification (often a phone call) before any change to the domain. In WHOIS/RDAP it appears as the registry-set serverTransferProhibited (plus serverUpdateProhibited and serverDeleteProhibited) status codes — the registry-level counterparts of the registrar-set clientTransferProhibited. Typically only offered for high-value domains and at a premium.
Registry operator#: The company that runs the technical backend of a TLD — maintaining the authoritative database of every domain in it and publishing the zone. Sometimes the same as the sponsor, sometimes a separate commercial operator.
Renewal date#: The deadline by which you must renew to keep a domain. Registrars send reminders and often auto-renew by default.
Renewal jump (promo trap)#: The gap between a low promotional first-year price and a much higher standard renewal — the biggest hidden cost in choosing a domain.
Reseller#: A company that sells domains under its own brand but through another company's ICANN accreditation, rather than holding its own. The accredited registrar behind it is the registrar of record. Website builders often resell.
Restricted TLD#: A TLD that limits who may register, by profession, location, or accreditation. Contrast with open TLDs anyone can buy.
Retail price#: The price you actually pay a registrar, made of the registry fee + ICANN fee + the registrar's markup, and shown as a first-year and a renewal figure.
Root zone#: The top of the DNS hierarchy, published by IANA, that lists every top-level domain and the nameservers authoritative for it.

S

Second-level domain#: The label directly to the left of the TLD — usually the part you actually register and brand.
serverHold / clientHold#: EPP status codes that remove a domain from the DNS zone so it stops resolving — set by the registry (server) or registrar (client), often over disputes or unpaid fees.
Sponsored TLD (sTLD)Sponsored Top-Level Domain#: A specialized gTLD with a defined community and eligibility rules enforced by a sponsor organisation.
Sponsoring organisation#: In the IANA root database, the organisation responsible for a top-level domain — for a ccTLD this is usually the country's government or a designated manager, distinct from any commercial registry operator that runs the backend.
Sponsoring registrar#: Another name for the registrar of record — the registrar that currently manages a domain and appears in its WHOIS/RDAP record.
SSL/TLS certificate#: A certificate that enables HTTPS by proving a site's identity and encrypting traffic. Free options (Let's Encrypt) mean you rarely need to buy one from a registrar.
Subdomain#: A label added in front of your domain to create a separate address, managed entirely through your own DNS at no extra registration cost.
Sunrise period#: The launch phase of a new TLD when trademark holders (validated via the TMCH) can register matching names before the general public.

T

Thick vs thin WHOIS#: Thick WHOIS keeps full registrant data at the registry; thin WHOIS (historically .com/.net) keeps it only at the registrar. Registries have been moving to thick models.
TLDTop-Level Domain#: Top-level domain — the last label of a domain name, after the final dot. TLDs are either generic (gTLDs like .com) or country-code (ccTLDs like .de).
Trade#: At some ccTLD registries, the formal process for changing a domain's owner (distinct from a registrar transfer), sometimes with its own fee and paperwork.
Trademark Clearinghouse (TMCH)Trademark Clearinghouse#: ICANN's central database of verified trademarks that powers new-gTLD rights protections like sunrise registration and trademark-claims notices.
Transfer-in#: The process of moving a domain into a registrar. For most gTLDs it adds one year of registration on top of the remaining time.
Transfer-out#: The process of releasing a domain from your current registrar: unlock it and provide the authorization code to the new one.
TTLTime To Live#: Time to live — how many seconds resolvers may cache a DNS record before re-checking. Lower it before a planned change so updates propagate faster.
TXT record#: A free-form text DNS record used for domain verification and email authentication (SPF, DKIM, DMARC).
Typosquatting#: Registering misspellings of popular domains to catch mistyped traffic, sometimes for ads or phishing.

U

UDRPUniform Domain-Name Dispute-Resolution Policy#: Uniform Domain-Name Dispute-Resolution Policy — ICANN's process for resolving trademark-based disputes over gTLD domains without going to court.
URSUniform Rapid Suspension#: Uniform Rapid Suspension — a faster, cheaper complement to UDRP for clear-cut trademark abuse that suspends (rather than transfers) the domain.

W

WHOIS#: A public directory protocol that returns ownership and contact information for a domain. Since the EU's GDPR took effect in 2018, registrant personal data is usually redacted in WHOIS output; registries and registrars retain the full records.
WHOIS / RDAP server#: The service that answers lookups about a domain's registration. WHOIS is the legacy text protocol; RDAP is its structured, access-controlled successor.
WHOIS accuracy#: ICANN requires registrants to provide accurate contact data and respond to verification; false or unresponsive WHOIS can lead to suspension.
WHOIS privacy#: A service where the registrar substitutes its own proxy contact details for the registrant's personal data in WHOIS queries. Free WHOIS privacy is now standard at most major registrars on gTLDs and many ccTLDs.
Wholesale price#: The price the registry charges registrars per year for a domain registration or renewal. ICANN-governed gTLDs have published wholesale prices; ccTLD wholesale prices are set by the country registry. Cloudflare Registrar's 'at cost' model means they charge wholesale + ICANN fee with no markup.

#

60-day transfer lock#: An ICANN policy that prevents a gTLD domain from being transferred to a different registrar within 60 days of a new registration, a previous transfer, or a registrant contact change. Owners can transfer-out earlier if they explicitly opt out at registration time (where supported).

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