(1):

(n.) Cotton or linen cloth suitable for bed sheets. It is sometimes made of double width.

(2):

(n.) A lining of planks or boards (rarely of metal) for protecting an embankment.

(3):

(p. pr. & vb. n.) of Sheet

(4):

(n.) The act or process of forming into sheets, or flat pieces; also, material made into sheets.