(1):

(n.) One who, or that which, lays.

(2):

(n.) That which is laid; a stratum; a bed; one thickness, course, or fold laid over another; as, a layer of clay or of sand in the earth; a layer of bricks, or of plaster; the layers of an onion.

(3):

(n.) A shoot or twig of a plant, not detached from the stock, laid under ground for growth or propagation.

(4):

(n.) An artificial oyster bed.