Definition of "martingale"

A piece of harness used on a horse to keep it from raising its head above a desired point.  examples

(nautical) A spar, or piece of rigging that strengthens the bowsprit.  examples

(mathematics) A stochastic process for which the conditional expectation of future values given the sequence of all prior values is equal to the current value.  examples

A gambling strategy in which one doubles the stake after each loss.  examples

(fencing) A strap attached to the sword handle, preventing a sword being dropped if disarmed.  examples

To employ the martingale strategy in gambling.  quotations  examples