Definition of nucleus accumbens in US English:

nucleus accumbens

noun

Anatomy
  • More fully "nucleus accumbens septi". A group of pleomorphic cells forming part of the mesolimbic system, located between the head of the caudate nucleus and the putamen, and involved in conditioned (especially appetitive) behaviours and substance abuse.

Origin

1920s; earliest use found in Philosophical Transactions of the Royal Society of London. From scientific Latin nucleus accumbens, short for nucleus accumbens septi from classical Latin nucleus + accumbēns + sēptī, genitive of sēptum.