(Physics)(物理)a discrete quantity of energy proportional in magnitude to the frequency of the radiation it represents 量子 ■an analogous discrete amount of any other physical quantity, such as momentum or electric charge (动量或电荷等物理值的)量子 ■(Physiology)the unit quantity of acetylcholine released at a neuromuscular junction by a single synaptic vesicle, contributing a discrete small voltage to the measured end-plate potential (生理)(乙酰胆碱释放的)单元量
a required or allowed amount, especially an amount of money legally payable in damages (尤指偿付损失的)定额,定量 ■a share or portion 份额,部分 each man has only a quantum of compassion. 每个人仅有部分的怜悯之情。
语源
mid 16th cent. (in the general sense 'quantity'): from Latin, neuter of quantus (see quantity). Sense 1 dates from the early 20th cent