Great Words In Science Number One: Martingale
In modern probability theory, a martingale is a random process which has an expected value equal to its current value. So if you are betting on someone flipping a coin over and over again and you are given fair 50/50 odds, your winnings constitute a martingale. It’s a totally unpredictable process, but in the long term your winnings are liable to go up as much as they go down. You can expect to finish with what you started with. (The idea of “expectation” has a rigorous definition but it means pretty much what you’d expect. Hey, that’s brilliant.)
In the non-mathematical world, the word refers variously to the gambling strategy where you double your stake if you lose (you can at least see the probability connection here), a bit of horse-riding kit to attach the reins to the saddle girth, and some sort of nautical stay or cleat to fasten some sprit or jib. But according to Rabelais’s Gargantua it refers to a naughty pair of hose which fasten at the back. Rabs refers to “…the martingale fashion of breeches, wherein is a spunghole with a drawbridge for the more easy caguing.”
My OED proffers these facts helplessly for the layman to ponder. If any readers can discover the connection between these meanings then please let the compilers know. You might also tell them they’ve left out “caguing”.