Source : Webster's Revised Unabridged Dictionary (1913)
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.
4. (Scots Law) A contract by which the use of a thing is set,
or let, for hire; a lease. --Burrill.
5. Confidence; reliance. [Prov. Eng.] --Halliwell.
{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.