Shoulder-of-mutton sail

(Naut.) a triangular sail of peculiar form. It is chiefly used to set on a boat's mast.
(Naut.) a triangular sail carried on a boat's mast; - so called from its shape.

See also: Sail, Shoulder

Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in classic literature ?
She sailed with what we call a shoulder-of-mutton sail; and the boom jibed over the top of the cabin, which lay very snug and low, and had in it room for him to lie, with a slave or two, and a table to eat on, with some small lockers to put in some bottles of such liquor as he thought fit to drink; and his bread, rice, and coffee.