n. (Naut.) the topsail on a foremast. See Sail. [ 1913 Webster + WordNet 1.5 ]
n. (Naut.) A small triangular sail having its foot extended upon the gaff and its luff upon the topmast. [ 1913 Webster ]
n. a topsail set on the mainmast. [ WordNet 1.5 ]
n. (Naut.) In a square-rigged vessel, the sail next above the lowermost sail on a mast. This sail is the one most frequently reefed or furled in working the ship. In a fore-and-aft rigged vessel, the sail set upon and above the gaff. See Cutter, Schooner, Sail, and Ship. [ 1913 Webster ]
Topsail schooner. (Naut.)