:of, relating to, or being a turning point or specially important juncture : such as
:relating to or being the stage of a disease at which an abrupt change for better or worse may be expected;
:being or relating to an illness or condition involving danger of death
- a patient listed in critical condition
:relating to or being a state in which or a measurement or point at which some quality, property, or phenomenon suffers a definite change
- a critical waterfowl habitat
- a component critical to the operation of a machine
:being in or approaching a state of crisis
:inclined to criticize severely and unfavorably
- His critical temperament cost him several friends.
:consisting of or involving criticism ;
:of or relating to the judgment of critics
- The play was a critical success.
:exercising or involving careful judgment or judicious evaluation
- a critical commentary on the mayor's proposal
:including variant readings and scholarly emendations
:of sufficient size to sustain a chain reaction
—used of a mass of fissionable material
:sustaining a nuclear chain reaction
- The reactor went critical.