What do you Mean by Canonical Name Record (CNAME)?

A Canonical Name Record is a type of resource record in the Domain Name System (DNS) that specifies that the domain name is an alias of another, canonical domain name.

This helps when running multiple services (like an FTP Server and a Web Server; each running on different ports) from a single IP address. Each service can then have its own entry in DNS (like ftp.example.com and www.example.com) [source: Wikipedia].