Domain glossary: registrar vs registry, WHOIS, DNS, and more

Domains come wrapped in a surprising amount of jargon — three near-identical “r” words for who does what, cryptic record types, lock statuses written in camelCase — so this glossary defines the terms an indie founder actually runs into, in plain English.

The name itself

Domain name — the human-readable address of a website or service, like domain.yoga. It has two core parts: the part you choose (left of the dot) and the extension (right of the dot).

Second-level domain (SLD) — the part of the domain you actually pick and pay for: “domain” in domain.yoga. It’s what most people mean when they say “the name.”

Subdomain — a prefix you create under a domain you already own, like blog.example.com or app.example.com. Subdomains are free and unlimited; you configure them in DNS, not at checkout.

TLD (top-level domain) — the extension after the last dot: .com, .de, .yoga. Each TLD has its own operator, pricing, and rules.

gTLD (generic TLD) — a TLD not tied to a country, like .com, .net, or .org. Usually open to anyone (a few, like .bank, are restricted) and governed by ICANN’s rules.

ccTLD (country-code TLD) — a two-letter TLD assigned to a country or territory, like .de (Germany) or .fr (France). Google normally geotargets them to that country, but as of 2026 it treats a list of popular ones — including .io, .co, .me, .tv, and .ai — as generic, with no automatic country targeting. Compare options in .com vs .io vs .ai vs .co.

New gTLD — one of the 1,200+ extensions delegated since ICANN’s 2012 expansion round, like .app, .dev, or .yoga. Google has stated it treats them like any other gTLD in ranking — no boost, no penalty.

Domain hack — a domain where the TLD completes the word or phrase, like domain.yoga reading as “domain yoga.” Full explainer in What is a domain hack?

Who’s who

Registry — the organization that operates a TLD’s master database and sets its wholesale price (for example, Verisign runs .com). You almost never buy from a registry directly.

Registrar — an accredited company that sells and manages domain registrations to the public — Namecheap, Cloudflare, Porkbun, and so on. It records your registration in the registry’s database and is where you manage renewals, contacts, and nameservers.

Registrant — you: the person or company that registers the domain and holds the rights to use and transfer it. Registry runs the TLD, registrar sells it, registrant owns the registration.

Reseller — a company that sells domains through another registrar’s accreditation rather than its own — common with hosting providers. Fine in practice, but support requests route through an extra layer.

ICANN — the nonprofit that coordinates the global domain name system: it accredits registrars, contracts with gTLD registries, and sets cross-industry policies like transfer and expiry rules.

The technical plumbing

DNS (Domain Name System) — the internet’s address book: a distributed system that translates human-readable domain names into the IP addresses and service records machines need.

Nameservers — the servers that answer DNS queries for your domain. You set them at your registrar; whoever runs your nameservers (often Cloudflare or your host) controls where your domain points.

A record — maps a name to a server’s IPv4 address (AAAA is the IPv6 equivalent).

CNAME record — makes one name an alias of another, e.g. pointing www.example.com at example.com or at your hosting platform’s address.

MX record — tells the world which mail servers receive email for your domain.

TXT record — holds arbitrary text; used for domain-ownership verification and email-authentication policies like SPF, DKIM, and DMARC.

Null MX — a special MX record (“0 .”, defined in RFC 7505) that explicitly declares a domain accepts no email — useful anti-spoofing hygiene for domains you don’t use for email.

DNS propagation — the delay while DNS resolvers around the world drop their cached copy of your old records and pick up new ones. Typically minutes to a day or two, governed by each record’s TTL (time to live).

DNSSEC — an extension that cryptographically signs DNS answers so resolvers can detect tampered or forged responses. Usually a one-toggle setting at registrars that support it.

SSL/TLS and HTTPS — TLS (still commonly called SSL) is the encryption protocol behind HTTPS; a domain-validated TLS certificate proves you control the domain and lets browsers show the padlock. Notably, some TLDs like .dev and .app are HSTS-preloaded in browsers, so every site under them must serve HTTPS.

Let’s Encrypt — a free, automated, nonprofit certificate authority. Most modern hosts use it (or an equivalent) to issue and renew certificates automatically, so HTTPS typically costs nothing and needs no manual steps.

Privacy and records

WHOIS — the decades-old public lookup system for a domain’s registration data: registrar, key dates, status codes, and (historically) the owner’s contact details.

RDAP (Registration Data Access Protocol) — WHOIS’s modern replacement: the same registration data delivered in a structured, machine-readable format over HTTPS. It is now mandatory for virtually all generic TLDs — ICANN sunset the WHOIS requirement on 28 January 2025 — with .com, .name and .post the only legacy exceptions still permitted to run WHOIS. Since most readers hold a .com, that exception is the one worth remembering.

WHOIS privacy / redaction — personal contact details are redacted from public lookups by default under ICANN’s Registration Data Policy, in effect since 21 August 2025 and superseding the 2018 Temporary Specification adopted in response to the GDPR. Registrar privacy services layer a forwarding proxy on top. Note the redaction protects natural persons: the EU’s NIS-2 Directive is pushing legal-entity data back into public view as member states transpose it. Details in GDPR, WHOIS privacy, and your domain.

Ownership and lifecycle

Registrar lock (clientTransferProhibited) — a status your registrar sets that blocks transfers to another registrar until you unlock it. It protects against hijacking and doesn’t affect DNS, renewal, or normal use.

Auth code (EPP code) — a password-like transfer code you obtain from your current registrar and give to the new one to authorize a transfer.

60-day transfer lock — ICANN policy: a domain can’t move to another registrar for 60 days after initial registration (and again after a transfer). ICANN’s Board approved shortening this to 30 days on 7 June 2026, but implementation has not started — the policy language still has to be drafted, and registrars have asked for an 18-month transition window after that. Treat 60 days as the real number for the foreseeable future. A separate part of the same reform removes the lock that currently follows a change of registrant altogether, moving that process into its own policy. It only blocks transfers — you can point DNS and launch immediately, as covered in the first hour after registering a domain.

Auto-renew — the registrar setting that charges you and renews the domain before it expires. The cheapest insurance in this glossary: it keeps the expiry lifecycle below from ever starting.

Expiry lifecycle — what happens if a domain isn’t renewed: first a registrar grace period (up to ~45 days, at the registrar’s discretion) where renewal costs the normal price; then a 30-day Redemption Grace Period where recovery is possible but typically carries a hefty extra fee; then ~5 days of “pending delete”; then the name drops and anyone can register it.

Premium / aftermarket domain — a name priced above standard rates, either by the registry (premium tiers on desirable names) or by an existing owner reselling it on the aftermarket. Some registry premiums also renew at the higher price — always check before buying.

Domain parking — holding a registered domain without a real site on it, often showing a placeholder or ad page. Common for names you’re reserving for later.

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If the jargon is the easy part and the hard part is finding a name that’s actually available, Domain Yoga generates brandable names and domain hacks with live availability — free to try.