quan·tum noun \ˈkwänt-əm\
plural quan·ta \ˈkwänt-ə\
: one of the very small increments or parcels into which many forms of energy are subdivided <a molecule of rhodopsin in the human eye can cause a response to a single quantum of light>
: one of the small molecular packets of a neurotransmitter (as acetylcholine) released into the synaptic cleft in the transmission of a nerve impulse across a synapse
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