Source : Webster's Revised Unabridged Dictionary (1913)

Wombat \Wom"bat\, n. [From the native name, womback, wombach, in
   Australia.] (Zo["o]l.)
   Any one of three species of Australian burrowing marsupials
   of the genus {Phascolomys}, especially the common species
   ({P. ursinus}). They are nocturnal in their habits, and feed
   mostly on roots.

Source : WordNet®

wombat
     n : burrowing herbivorous Australian marsupials about the size
         of a badger

Source : Free On-Line Dictionary of Computing

WOMBAT
     
        Waste Of Money, Brains, And Time.
     
        Problems which are both profoundly {uninteresting} in
        themselves and unlikely to benefit anyone interesting even if
        solved.  Often used in fanciful constructions such as
        "wrestling with a wombat".
     
        See also {crawling horror}, {SMOP}.
     
        [{Jargon File}]
     
        (1995-03-10)

wombat
     
        1.  A {metasyntactic variable} in {Commonwealth
        Hackish}.
     
        2.  {wombat.doc.ic.ac.uk}.
     
        [{Jargon File}]
     
        (1995-03-10)