What is "grampus griseus"

orc \orc\ ([^o]rk), n. [L. orca, a kind of whale: cf. F. orque.]

1. (Zo["o]l.) Any of several cetaceans, especialy the grampus ( Grampus griseus) of the dolphin family. [Written also ork and orch.]
   --Milton.

   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.

   Goblins, hobgoblins, and orcs of the worst description.
   --J. J. Tolkien (The Hobbit)

3. The orca.