Tack, n.
 1. A small, short, sharp-pointed nail, usually having a broad, flat head.
 2. That which is attached; a supplement; an appendix. See Tack, v. t., 3.
    Some tacks had been made to money bills in King Charles's time.   --Bp. Burnet.
 3. Naut. (a) A rope used to hold in place the foremost lower corners of the courses when the vessel is closehauled (see Illust. of Ship); also, a rope employed to pull the lower corner of a studding sail to the boom. (b) The part of a sail to which the tack is usually fastened; the foremost lower corner of fore-and-aft sails, as of schooners (see Illust. of Sail). (c) The direction of a vessel in regard to the trim of her sails; as, the starboard tack, or port tack; -- the former when she is closehauled with the wind on her starboard side; hence, the run of a vessel on one tack; also, a change of direction; as, to take a different tack; -- often used metaphorically.
 4. Scots Law A contract by which the use of a thing is set, or let, for hire; a lease.
 5. Confidence; reliance. [Prov. Eng.]
 Tack of a flag Naut., a line spliced into the eye at the foot of the hoist for securing the flag to the halyards.
 Tack pins Naut., belaying pins; -- also called jack pins.
 To haul the tacks aboard Naut., to set the courses.
 To hold tack, to last or hold out. --Milton.