The Collaborative International Dictionary of English v.0.48:

Pitta \Pit"ta\ (p[i^]t"t[.a]), n. (Zool.)
   Any one of a large group of bright-colored clamatorial birds
   belonging to Pitta, and allied genera of the family
   Pittid[ae]. Most of the species are varied with three or
   more colors, such as blue, green, crimson, yellow, purple,
   and black. They are called also ground thrushes, and Old
   World ant thrushes; but they are not related to the true
   thrushes.
   [1913 Webster]

   Note: The pittas are most abundant in the East Indies, but
         some inhabit Southern Asia, Africa, and Australia. They
         live mostly upon the ground, and feed upon insects of
         various kinds.
         [1913 Webster]

WordNet (r) 3.0 (2006):

pitta
    n 1: any bird of the genus Pitta; brilliantly colored chiefly
         terrestrial birds with short wings and tail and stout bills