A Sail

(nautical) A piece of fabric attached to a boat and arranged such that it causes the wind to drive the boat along. The sail may be attached to the boat via a combination of mast, spars and ropes.
(nautical, uncountable) The concept of a sail or sails, as if a substance.
(uncountable) The power harnessed by a sail or sails, or the use of this power for travel or transport.
A trip in a boat, especially a sailboat.
(dated, plural "sail") A sailing vessel; a vessel of any kind; a craft.
(nautical) The conning tower of a submarine.
The blade of a windmill.
A tower-like structure found on the dorsal (topside) surface of submarines.
The floating organ of siphonophores, such as the Portuguese man-of-war.
(fishing) A sailfish.
(paleontology) an outward projection of the spine, occurring in certain dinosaurs and synapsids
Anything resembling a sail, such as a wing.