A CNAME (Canonical Name) record is a DNS record that aliases one domain name to another. Instead of pointing to an IP address, a CNAME points to another domain name, which is then resolved. For example, "www.example.com" might have a CNAME pointing to "example.com." CNAMEs cannot be used at the root/apex of a domain (you can't set a CNAME for "example.com" itself).