midbrainWiktionary 原文英美构词拆解midmid-前缀brainbrain词干mid-Denoting the middle part. · Occupying a middle position.词源说明From mid- + brain.释义名词noun1(neuroanatomy) A part of the brain located rostral to the pons and caudal to the thalamus and the basal ganglia, composed of the tectum (dorsal portion) and the tegmentum (ventral portion).