The Free On-line Dictionary of Computing (30 December 2018):

canonical name

   (CNAME) A host's official name as opposed to an alias.  The
   official name is the first hostname listed for its Internet
   address in the hostname database, /etc/hosts or the
   Network Information Service (NIS) map hosts.byaddr ("hosts"
   for short).  A host with multiple network interfaces may have
   more than one Internet address, each with its own canonical
   name (and zero or more aliases).

   You can find a host's canonical name using nslookup if you
   say

   	set querytype=CNAME

   and then type a hostname.

   (1994-11-29)