Luff n.  Naut. (a) The side of a ship toward the wind. (b) The act of sailing a ship close to the wind. (c) The roundest part of a ship's bow. (d) The forward or weather leech of a sail, especially of the jib, spanker, and other fore-and-aft sails.
 Luff tackle, a purchase composed of a double and single block and fall, used for various purposes. --Totten.
 Luff upon luff, a luff tackle attached to the fall of another luff tackle. --R. H. Dana, Jr.