noun
: any of the nerves that arise from the vertebrate brain, pass through openings in the skull to the periphery of the body (as the head), comprise 12 pairs in reptiles, birds, and mammals and usually 10 in fishes and amphibians, and are sensory, motor, or mixed in constitution — see abducens nerve , accessory nerve , auditory nerve , facial nerve , glossopharyngeal nerve , hypoglossal nerve , oculomotor nerve , olfactory nerve , optic nerve , trigeminal nerve , trochlear nerve , vagus nerve