what is sea oat
Definition of sea oat. 1  1 : a tall grass (Uniola paniculata) that has panicles resembling those of the oat, grows on the coast of the southern U.S., and is useful as a sand binder âusually used in plural. 2  2 sea oats plural : a cluster of yellowish vase-shaped egg cases of a whelk of the genus Thais : sea corn.