GNU Collaborative International Dictionary of English

Found one definition

1.       
   orc (ôrk), n. [L. orca, a kind of whale: cf. F. orque.]
   1. (Zool.) Any of several cetaceans, especialy the grampus (Grampus griseus) of the dolphin family. [Written also ork and orch.]  Milton.
   
   [1913 Webster]
   
   An island salt and bare,
   
   The haunt of seals, and orcs, and sea-mews' clang. Milton (Par. Lost xi. 835).
   
   
   2. (Mythology) A mythical monster of varying descriptions; an ogre.
   
   [PJC]
   
   Goblins, hobgoblins, and orcs of the worst description. J. J. Tolkien (The Hobbit)
   
   
   3. The orca.
   
   [PJC]