Lāp1, n.
n. [A-S. læppa, lappa, D. & Dan. lap, Sw. lapp, Icel. lappi, O. H. Ger. & O. L. Ger. lappā, L. Ger. lappe, N. H. Ger. lappen.]
Sense 1. The loose part of a coat; the lower part of a garment that plays loosely; an apron.
Sense 2. The part of the clothing that lies on the knees when a person sits down; that part of the body thus covered.
Men expect that happiness should drop into their laps. Tillotson.
Sense 3. That part of any substance or fixture which extends over or lies upon another; as, the lap of a board; also, an edge; a border or hem.
At first he tells a lie with some shame and reluctancy. . . . For then, if he cuts off but a lap of truth’s garment, his heart smites him. Fuller.
Sense 4. (Mach.) A piece of brass, lead, or other soft metal, used to hold a cutting or polishing powder in cutting glass, gems, and the like, or in polishing cutlery, &c. It is usually in the form of a wheel or disk, which revolves rapidly.
Sense 5. (Steam-eng.) The amount by which a slide-valve, at its half-stroke, overlaps a steam-port, either internally or externally.
☞ When used alone, it means outside-lap, or lap on the steam side. Inside-lap means lap on the exhaust side.