- the smallest quantity of some physical property, such as energy, that a system can possess according to the quantum theory
- a particle with such a unit of energy
- amount or quantity, esp a specific amount
- (modifier) loosely, sudden, spectacular, or vitally important: a quantum improvement
WordReference Random House Learner's Dictionary of American English © 2026
quan•tum /ˈkwɑntəm/USA pronunciation
n., pl. -ta adj.
n. [countable]
adj. [before a noun]
WordReference Random House Unabridged Dictionary of American English © 2026n. [countable]
- quantity or amount:the least quantum of evidence.
- Physicsthe smallest amount by which certain particles in physics can possess, absorb, give off, or change their amount of energy.
adj. [before a noun]
- of or relating to the study in physics of the smallest amount of energy a particle can possess, absorb, or give off:quantum physics.
- sudden and significant:a quantum increase.
quan•tum
(kwon′təm),USA pronunciation n., pl. -ta (-tə),USA pronunciation
adj.
n.
adj.
n.
- quantity or amount:the least quantum of evidence.
- a particular amount.
- a share or portion.
- a large quantity;
bulk. - Physics
- the smallest quantity of radiant energy, equal to Planck's constant times the frequency of the associated radiation.
- the fundamental unit of a quantized physical magnitude, as angular momentum.
adj.
- sudden and significant:a quantum increase in productivity.
- noun, nominal use of neuter of Latin quantus how much 1610–20
Collins Concise English Dictionary © HarperCollins Publishers::
quantum /ˈkwɒntəm/ n ( pl -ta /-tə/)
'quantum' also found in these entries (note: many are not synonyms or translations):
antiparticle
- Bohr
- Born
- Bose-Einstein statistics
- charm
- classical
- Copenhagen interpretation
- corpuscular theory
- de Broglie
- decoherence
- degenerate matter
- energy band
- Fermi-Dirac statistics
- forbidden
- Franck
- graviton
- Hertz
- hole
- Landau
- lepton number
- mechanics
- -on
- parity
- Pauli exclusion principle
- phonon
- photon
- physics
- Planck constant
- QED
- quanta
- quantize
- quantum computer
- quantum electrodynamics
- quantum mechanics
- quantum meruit
- quantum number
- quantum teleportation
- quantum theory
- qubit
- research quantum
- shell
- spin
- strangeness
- Townes
- uncertainty principle
- wave mechanics
- allowed
- antibaryon
- asymptotic freedom
- axion