quan|tum

quan|tum «KWON tuhm», noun, plural -ta, adjective.

–n.

1. Physics. a) the basic unit of radiant energy; the smallest amount of energy capable of existing independently. Light and heat are given off and absorbed in quanta. »

One radiation quantum can modify the nucleus of a germ cell sufficiently to cause a mutation, an inheritable change of character; but only one in many million quanta will score that kind of bull's eye (Atlantic).

b) this amount of energy regarded as a unit.

2. a sum; amount; quantity; share or portion: »

Every member pressing forward to throw on his quantum of wisdom, the subject was quickly buried under a mountain of words (Washington Irving).

–adj.

of sudden, spectular significance or effect, often representing a major advance: »

the dry, electrostatic copying process, a quantum improvement over earlier wet photographic methods (Time).

╂[< Latin quantum, neuter adjective, how(ever) much]