adj. 1 a making or involving adverse or censorious comments or judgements. b expressing or involving criticism. 2 skilful at or engaged in criticism. 3 providing textual criticism (a critical edition of Milton). 4 a of or at a crisis; involving risk or suspense (in a critical condition; a critical operation). b decisive, crucial (of critical importance; at the critical moment). 5 a Math. & Physics marking transition from one state etc. to another (critical angle). b Physics (of a nuclear reactor) maintaining a self-sustaining chain reaction. critical apparatus = APPARATUS 4. critical mass Physics the amount of fissile material needed to maintain a nuclear chain reaction. critical path the sequence of stages determining the minimum time needed for an operation. critical temperature Chem. the temperature above which a gas cannot be liquefied. criticality n. (in sense 5). critically adv. criticalness n.
[ L criticus: see CRITIC ]