1814, from craunch (1630s), probably of imitative origin. The noun is 1836, from the verb; the sense of "critical moment" was popularized by Winston Churchill, whose first recorded use of it was in 1939.
A crisis; a desperate climax; squeeze: Then came the political conventions that summer, and more crunches/ A ''crunch'' is characterized by a skyrocketing of interest rates and a choking off of the availability of credit/ The ''crunch'' between press and Government is inevitable in American affairs(1930s+)
Akindof exercise for the stomach, in which one pulls the head off the floor while lying on one's back: Actress Julianne Phillips keeps her stomach flat by doing 6,000 ''crunches'' a week(1990s+)
To process, usually in a wearisome way (1980s+ Computer)