the acetic acid ester of choline, (CH)N(OH)CHCHOCOCH, found in many body tissues, esp. at neuromuscular junctions, acting as a nerve impulse transmitter: its chloride or bromide is used in medicine for various disorders
See acetylcholine in American Heritage Dictionary 4
(ə-sētˌl-kōˈlēnˌ)
noun
A white crystalline derivative of choline, C7H17NO3, that is released at the ends of nerve fibers in the somatic and parasympathetic nervous systems and is involved in the transmission of nerve impulses in the body.