Source : Webster's Revised Unabridged Dictionary (1913)

Grouper \Group"er\, n. [Corrupted fr. Pg. garupa crupper. Cf.
   {Garbupa}.] (Zo["o]l.)
   (a) One of several species of valuable food fishes of the
       genus {Epinephelus}, of the family {Serranid[ae]}, as the
       red grouper, or brown snapper ({E. morio}), and the black
       grouper, or warsaw ({E. nigritus}), both from Florida and
       the Gulf of Mexico.
   (b) The tripletail ({Lobotes}).
   (c) In California, the name is often applied to the
       rockfishes. [Written also {groper}, {gruper}, and
       {trooper}.]

Source : WordNet®

grouper
     n 1: flesh of a saltwater fish similar to sea bass
     2: usually solitary bottom sea basses of warm seas