Slab (?), n. [OE. slabbe, of uncertain origin; perhaps originally meaning, a smooth piece, and akin to slape, Icel. sleipr slippery, and E. slip, v. i.] 1. A thin piece of anything, especially of marble or other stone, having plane surfaces. Gwilt.
2. An outside piece taken from a log or timber in sawing it into boards, planks, etc.
3. (Zoöl.) The wryneck.
4. (Naut.) The slack part of a sail.
Slab line(Naut.), a line or small rope by which seamen haul up the foot of the mainsail or foresail. Totten.