Definify.com
Webster 1913 Edition
Tridacna
‖
Tri-dac′na
,Noun.
[L., pl., a kind of oysters, fr. Gr. [GREEK] eaten at three bites, [GREEK] tri- + [GREEK] to bite.]
(Zool.)
A genus of very large marine bivalve shells found on the coral reefs of the Indian and Pacific Oceans. One species (
Tridacna gigas
) often weighs four or five hundred pounds, and is sometimes used for baptismal fonts. Called also paw shell
, and fountain shell
.