A domain name registrar is a company accredited by the Internet Corporation for Assigned Names and Numbers (ICANN) and/or by a national ccTLD authority to register Internet domain names.

ICANN has authority over gTLDs (Generic Top Level Domains). Examples of gTLDs include .com, .org and .net. ICANN doesn't have authority over ccTLDs (Country Code Top-Level Domains), though it is quite common for domain name registrars to offer ccTLD registration services as well. Most registrars provide the Domain Name System (DNS) hosting service, but this is not required, and is often considered a separate service.