from
The Collaborative International Dictionary of English v.0.48
Sloop \Sloop\, n.[D. sloep, of uncertain origin. Cf. {Shallop}.]
1. (Naut.) A vessel having one mast and fore-and-aft rig,
consisting of a boom-and-gaff mainsail, jibs, staysail,
and gaff topsail. The typical sloop has a fixed bowsprit,
topmast, and standing rigging, while those of a cutter are
capable of being readily shifted. The sloop usually
carries a centerboard, and depends for stability upon
breadth of beam rather than depth of keel. The two types
have rapidly approximated since 1880. One radical
distinction is that a sloop may carry a centerboard. See
{Cutter}, and Illustration in Appendix.
[1913 Webster]
2. (Naut.) In modern usage, a sailing vessel having one mast,
commonly with a Bermuda rig, with either a center-board or
a keel. In the United States, a sloop may have one or two
headsails, while in Western Europe and Great Britain a
sloop has only one headsail.
[RDH]
{Sloop of war}, formerly, a vessel of war rigged either as a
ship, brig, or schooner, and mounting from ten to
thirty-two guns; now, any war vessel larger than a
gunboat, and carrying guns on one deck only.
[1913 Webster]