n. 1. (Zool.) The thin, new growth around the edge of a shell, of an oyster. [ 1913 Webster ]

2. Any thin, as on a board or a razor. [ 1913 Webster ]

a. Having a feather-edge; also, having one edge thinner than the other, as a board; -- in the United States, said only of stuff one edge of which is made as thin as practicable. [ 1913 Webster ]