Source : Webster's Revised Unabridged Dictionary (1913)

Pika \Pi"ka\, n. (Zo["o]l.)
   Any one of several species of rodents of the genus {Lagomys},
   resembling small tailless rabbits. They inhabit the high
   mountains of Asia and America. Called also {calling hare},
   and {crying hare}. See {Chief hare}.

Source : WordNet®

pika
     n : small short-eared burrowing mammal of rocky uplands of Asia
         and western North America [syn: {mouse hare}, {rock
         rabbit}, {coney}, {cony}]