The Collaborative International Dictionary of English v.0.48:
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
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.