Meaning of QUANTUM in English

QUANTUM

n. (pl. quanta) 1 Physics a a discrete quantity of energy proportional in magnitude to the frequency of radiation it represents. b an analogous discrete amount of any other physical quantity. 2 a a required or allowed amount. b a share or portion. quantum jump (or leap) 1 a sudden large increase or advance. 2 Physics an abrupt transition in an atom or molecule from one quantum state to another. quantum mechanics (or theory) Physics a system or theory using the assumption that energy exists in discrete units.

[ L, neut. of quantus how much ]

Concise Oxford English dictionary.      Краткий оксфордский словарь английского языка.