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Corners – The names of corners of sails vary, depending on shape and symmetry. In a triangular sail, the corner where the luff and the leech connect is called the head.[40][35] On a square sail, the top corners are head cringles, where there are grommets, called cringles.[41] On a quadrilateral sail, the peak is the upper aft corner of the sail, at the top end of a gaff or other spar. The throat is the upper forward corner of the sail, at the bottom end of a gaff or other spar. Gaff-rigged sails, and certain similar rigs, employ two halyards to raise the sails: the throat halyard raises the forward, throat end of the gaff, while the peak halyard raises the aft, peak end.[42]
The corner where the leech and foot connect is called the clew on a fore-and-aft sail. On a jib, the sheet is connected to the clew; on a mainsail, the sheet is connected to the boom (if present) near the clew.[35] Clews are the lower two corners of a square sail. Square sails have sheets attached to their clews like triangular sails, but the sheets are used to pull the sail down to the yard below rather than to adjust the angle it makes with the wind.[42] The corner where the leech and the foot connect is called the clew.[35] The corner on a fore-and-aft sail where the luff and foot connect is called the tack[35] and, on a mainsail, is located where the boom and mast connect.[35]