Crisis \Cri"sis\ (kr?"s?s), n.; pl. Crises (-s?z). [L. crisis, Gr. ????, fr. ???? to separate. See Certain.]

1. The point of time when it is to be decided whether any affair or course of action must go on, or be modified or terminate; the decisive moment; the turning point.

This hour's the very crisis of your fate. --Dryden.

The very times of crisis for the fate of the country. --Brougham.

2. (Med.) That change in a disease which indicates whether the result is to be recovery or death; sometimes, also, a striking change of symptoms attended by an outward manifestation, as by an eruption or sweat.

Till some safe crisis authorize their skill. --Dryden.

Source: Webster's Revised Unabridged Dictionary (1913)