from
The Collaborative International Dictionary of English v.0.48
lateen sail \lateen sail\ n. [F. voile latine a sail in the
shape of a right-angled triangle; cf. It. & Sp. vela latina;
properly Latin sail. See {Latin}.] (Naut.)
A triangular sail, extended by a long yard, which is slung at
about one fourth of its length from the lower end, to a low
mast, this end being brought down at the tack, while the
other end is elevated at an angle or about forty-five
degrees; -- used in small boats, feluccas, xebecs, etc.,
especially in the Mediterranean and adjacent waters. Some
lateen sails have also a boom on the lower side.
[1913 Webster]