(1):

(n.) A thin plate or scale; a layer or coat lying over another; - said of thin plates or platelike substances, as of bone or minerals.

(2):

(n.) A thin plate or scale; specif., one of the thin, flat processes composing the vane of a feather.

(3):

(n.) The blade of a leaf; the broad, expanded portion of a petal or sepal of a flower.