say it: KWAHN-tuhm
quantum is a noun meaning "a discrete amount of something that is analogous to the quantities in quantum theory". It carries 2 recorded senses.
a discrete amount of something that is analogous to the quantities in quantum theory
(physics) the smallest discrete quantity of some physical property that a system can possess (according to quantum theory)
physics
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for quantum come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.