martingale

Meanings

1. A piece of harness used on a horse to keep it from raising its head above a desired point.
2. A spar, or piece of rigging that strengthens the bowsprit.
3. A stochastic process for which the conditional expectation of future values given the sequence of all prior values is equal to the current value.
4. A gambling strategy in which one doubles the stake after each loss.
5. A strap attached to the sword handle, preventing a sword being dropped if disarmed.

1. To employ the martingale strategy in gambling.

Etymology

From Middle French martingale, from Occitan martegalo, feminine form of martegal, an inhabitant of Martigues, which is from Latin maritima. Possibly merged with Spanish almártaga. The meaning in gambling may come from an old usage of "à la martingale" to mean absurdly, foolishly.https://people.math.harvard.edu/~ctm/home/text/class/sem/html/home/notes/martingales/martingales.pdf