域名注册商（英语：domain name registrar）是一个商业实体或组织，它们由互联网名称与数字地址分配机构（ICANN）或者一个国家性的国家代码顶级域名（ccTLD）域名注册局委派，以在指定的域名注册数据库中管理互联网域名，向公众提供此类服务。
英语百科
Domain name registrar 域名注册商
A domain name registrar is an organization or commercial entity that manages the reservation of Internet domain names. A domain name registrar must be accredited by a generic top-level domain (gTLD) registry and/or a country code top-level domain (ccTLD) registry. The management is done in accordance with the guidelines of the designated domain name registries.