Pronunciation: (kwon'tum), [key]
—n., pl. -taPronunciation: (-tu), [key]
1. quantity or amount: the least quantum of evidence.
2. a particular amount.
3. a share or portion.
4. a large quantity; bulk.
a. the smallest quantity of radiant energy, equal to Planck's constant times the frequency of the associated radiation.
b. the fundamental unit of a quantized physical magnitude, as angular momentum.
sudden and significant: a quantum increase in productivity.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.