'Fornix' definitions:

Definition of 'fornix'

From: WordNet
noun
Generally any arch shaped structure (but often it refers to the arched roof of an anatomical space)
noun
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 [syn: fornix, trigonum cerebrale]

Definition of 'Fornix'

From: GCIDE
  • Fornix \For"nix\, n.; pl. Fornices. [L., an arch.] (Anat.) (a) An arch or fold; as, the fornix, or vault, of the cranium; the fornix, or reflection, of the conjuctiva. (b) Esp., two longitudinal bands of white nervous tissue beneath the lateral ventricles of the brain. [1913 Webster]