\Mar"tin*gale\, Martingal \Mar"tin*gal\, n. [F.
martingale; cf. It. martingala a sort of hose, martingale,
Sp. martingala a greave, cuish, martingale, Sp. alm['a]rtaga
a kind of bridle.]
1. A strap fastened to a horse's girth, passing between his
   fore legs, and fastened to the bit, or now more commonly
   ending in two rings, through which the reins pass. It is
   intended to hold down the head of the horse, and prevent
   him from rearing.
2. (Naut.) A lower stay of rope or chain for the jib boom or
   flying jib boom, fastened to, or reeved through, the
   dolphin striker. Also, the dolphin striker itself.
3. (Gambling) The act of doubling, at each stake, that which
   has been lost on the preceding stake; also, the sum so
   risked; -- metaphorically derived from the bifurcation of
   the martingale of a harness. [Cant] --Thackeray.