Source : Webster's Revised Unabridged Dictionary (1913)

Herbivore \Her"bi*vore\, n. [Cf. F. herbivore.] (Zo["o]l.)
   One of the Herbivora. --P. H. Gosse.

Source : WordNet®

herbivore
     n : any animal that feeds chiefly on grass and other plants;
         "horses are herbivores"; "the sauropod dinosaurs were
         apparently herbivores"