Meaning of QUANTUM in English

/ ˈkwɒntəm; NAmE ˈkwɑːn-/ noun

( pl. quanta / -tə; NAmE /) ( physics ) a very small quantity of electromagnetic energy



mid 16th cent. (in the general sense quantity ): from Latin , neuter of quantus how great, how much. The current sense dates from the early 20th cent.

Oxford Advanced Learner's English Dictionary.      Оксфордский английский словарь для изучающик язык на продвинутом уровне.