The word craps, the dice game, comes from the word crab and is unrelated to the slang term for excrement. It is a French corruption of the English crabs which stood for a throw of two or three. Why the English called such a toss crabs is not known, but it could be related not to the crustacean, but rather to the apple, which is sour and undesirable. It dates at least to 1768. From a letter by Lord Carlisle written to George Selwin in that year:
If you are still so foolish, and will play, the best thing I can wish you is, that you may win and never throw crabs.
But the modern form craps does not appear until the mid-19th century. From J.H. Greene’s Exposure of Arts and Miseries of Gambling (1843):
The game of craps...is a game lately introduced into New Orleans, and is fully equal to faro in its...ruinous effects.
(Source: Oxford English Dictionary, 2nd Edition)
Copyright 1997-2013, by David Wilton