Meaning of Tridacna*

Tri•dac•na

Pronunciation: (tri-dak'nu), [key]
— n.
  1. a genus of giant clams inhabiting reefs in the South Pacific, attaining a diameter of 4 ft. (1.2 m) or more, and weighing over 500 lb. (227 kg).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.