'Sea turtle' definitions:

Definition of 'sea turtle'

noun

Any of various large turtles with limbs modified into flippers; widely distributed in warm seas [syn: sea turtle, marine turtle]

From: GCIDE

Sea turtle \Sea" tur"tle\ (Zool.) (a) Any one of several very large species of chelonians having the feet converted into paddles, as the green turtle, hawkbill, loggerhead, and leatherback. They inhabit all warm seas. (b) The sea pigeon, or guillemot. [1913 Webster]