from the GNU version of the Collaborative International Dictionary of English
- n. Any of several cetaceans, especialy the grampus (Grampus griseus) of the dolphin family.
- n. A mythical monster of varying descriptions; an ogre.
- n. The orca.
from The Century Dictionary and Cyclopedia
- n. A marine mammal; some cetacean, perhaps a grampus or killer, or the narwhal. See Orca.
From Middle French orque, Italian orca, and their source, Latin orca ("type of whale"). (Wiktionary)
Probably from Italian orco ("man-eating giant"); later revived by J. R. R. Tolkien, partly after Old English orc ("demon"). (Wiktionary)