quantum

quan·tum

noun \ˈkwänt-əm\

plural quan·ta \ˈkwänt-ə\

Definition of QUANTUM

1

: 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>

2

: 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