Why is it that
All hostnames are domain names, but not all domain names are hostnames.
Source: http://answers.yahoo.com/question/index?qid=20070820080918AA2kINu, also quoted as an answer in http://superuser.com/questions/59093/difference-between-host-name-and-domain-name
Shouldn't it be the other way round? All domain names are actually host names but not all hostnames are domain names?