[ kwon-tuh m ]
/ ˈkwɒn təm /

noun, plural quan·ta [kwon-tuh] /ˈkwɒn tə/.

quantity or amount: the least quantum of evidence.
a particular amount.
a share or portion.
a large quantity; bulk.
  1. the smallest quantity of radiant energy, equal to Planck's constant times the frequency of the associated radiation.
  2. the fundamental unit of a quantized physical magnitude, as angular momentum.


sudden and significant: a quantum increase in productivity.

Nearby words

  1. quantize,
  2. quantometer,
  3. quantong,
  4. quantrill,
  5. quantrill, william clarke,
  6. quantum bit,
  7. quantum chemistry,
  8. quantum chromodynamics,
  9. quantum computer,
  10. quantum cryptography

Origin of quantum

1610–20; noun use of neuter of Latin quantus how much

quantum sufficit

[ kwahn-too m soof-i-kit; English kwon-tuh m suhf-uh-sit ]
/ ˈkwɑn tʊm ˈsuf ɪ kɪt; English ˈkwɒn təm ˈsʌf ə sɪt /

adverb Latin.

as much as suffices; enough.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for quantum

British Dictionary definitions for quantum


/ (ˈkwɒntəm) /

noun plural -ta (-tə)

  1. the smallest quantity of some physical property, such as energy, that a system can possess according to the quantum theory
  2. a particle with such a unit of energy
amount or quantity, esp a specific amount
(often used with a negative) the least possible amount that can sufficethere is not a quantum of evidence for your accusation
something that can be quantified or measured
(modifier) loosely, sudden, spectacular, or vitally importanta quantum improvement

Word Origin for quantum

C17: from Latin quantus (adj) how much

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for quantum


[ kwŏntəm ]

n. pl. quan•ta (-tə)

The smallest amount of a physical quantity that can exist independently, especially a discrete quantity of electromagnetic radiation.
This amount of energy regarded as a unit.
A quantity or an amount.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for quantum


[ kwŏntəm ]

Plural quanta

A discrete, indivisible manifestation of a physical property, such as a force or angular momentum. Some quanta take the form of elementary particles; for example, the quantum of electromagnetic radiation is the photon, while the quanta of the weak force are the W and Z particles. See also quantum state.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.