Source : Webster's Revised Unabridged Dictionary (1913)

Moo \Moo\, a., adv., & n.
   See {Mo}. [Obs.] --Chaucer.

Moo \Moo\, v. i. [imp. & p. p. {Mooed}; p. pr. & vb. n.
   {Mooing}.] [Of imitative origin.]
   To make the noise of a cow; to low; -- child's word.

Moo \Moo\, n.
   The lowing of a cow.

Source : WordNet®

moo
     n : the sound made by a cow or bull

moo
     v : make a low noise, characteristic of bovines [syn: {low}]

Source : Free On-Line Dictionary of Computing

MOO
     
        {MUD Object Oriented}