fornix > define

noun

• Generally any arch shaped structure (but often it refers to the arched roof of an anatomical space. )
• An arched bundle of white fibers at the base of the brain by which the hippocampus of each hemisphere projects to the contralateral hippocampus and to the thalamus and mamillary bodies.
  • synonyms: trigonum cerebrale

• (n.) An arch or fold; as, the fornix or vault, of the cranium; the fornix or reflection, of the conjuctiva.
• (n.) Esp., two longitudinal bands of white nervous tissue beneath the lateral ventricles of the brain.