1. (n.) An arch or fold; as, the fornix, or vault, of the cranium; the fornix, or reflection, of the conjuctiva.

2. (n.) Esp., two longitudinal bands of white nervous tissue beneath the lateral ventricles of the brain.

arachnoid arbor vitae archipallium between brain brain stem cerebellar hemispheres cerebral cortex cerebrospinal fluid cerebrum convolution corpus callosum corpus striatum diencephalon dura mater endbrain fissure folia forebrain fornix frontal lobe glial cells globus pallidus gray matter gyrus hindbrain hippocampus hypothalamus lenticular nucleus limbic lobe little brain lobe mantle medulla oblongata meninges mesencephalon metencephalon midbrain myelencephalon neopallium occipital lobe optic chiasm pallium parietal lobe pia mater pineal body pituitary body pons reticular system rhombencephalon subthalamus telencephalon temporal lobe thalamus ventricle vermis white matter