Sail
a piece of canvas cloth spread to catch the wind, so as to cause or assist in causing a ship or boat to move through the water. Sails are supported by the masts, spars, or stays of the vessel, and take their names from the mast, yard, or stay on which they are stretched, as the mainsail, etc. The upper edge of a sail is the head, the lower edge the foot, the vertical edge the leech, the weather side or edge (that is, the side or edge next the mast or stay to which it is attached) of tay any but a square-sail is the luff, and the other edge the after leech. The clews or clues are the lower corners of a square sail, or the lower after corner of a foreand-aft sail. A tack is the lower weather corner of a square sail, or the lower for-