1.Definition: at or of a point at which a property or phenomenon suffers an abrupt change especially having enough mass to sustain a chain reaction
"A critical temperature of water is 100 degrees C--its boiling point at standard atmospheric pressure", "Critical mass", "Go critical"
2.Definition: being in or verging on a state of crisis or emergency
"A critical shortage of food", "A critical illness", "An illness at the critical stage"
3.Definition: characterized by careful evaluation and judgment
"A critical reading", "A critical dissertation", "A critical analysis of Melville's writings"
4.Definition: forming or having the nature of a turning point or crisis
"A critical point in the campaign", "The critical test"
5.Definition: marked by a tendency to find and call attention to errors and flaws
"A critical attitude"
6.Definition: of or involving or characteristic of critics or criticism
7.Definition: urgently needed; absolutely necessary
"A critical element of the plan", "Critical medical supplies"