A
DNS record type as per
RFC 1035.
CNAME in this context is short for canonical name. This versatile type of record allows one to map a hostname to another hostname. Such is useful when you have no control over your desired IP target. For example, if your domain was foo.com, and your ISP's news server was news.ISP.com, you could CNAME news.foo.com to news.ISP.com, thus allowing your ISP ultimate control over the location of their server, but keeping your hostname (news.foo.com) static (i.e. You wouldn't have to update an A record every time your ISP's news server IP address changed).