critical(redirected from embryological critical period)
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1. Informal so seriously injured or ill as to be in danger of dying
2. Physics of, denoting, or concerned with a state in which the properties of a system undergo an abrupt change
3. go critical (of a nuclear power station or reactor) to reach a state in which a nuclear-fission chain reaction becomes self-sustaining
Capable of sustaining a chain reaction at a constant level.