- noun Abbreviation for the class of games which in this
dictionary are described as MUAs. The logical progression for
people who know insufficient about the history of MUAs to
choose the dominant usage MUD (sense 6), but enough about
alternatives to realise that MOO doesn't begin with "MU". What
they'll do when they come across MUA servers which don't even
begin with "M" is anyone's guess - *, maybe? See also MU*.