adj. & n.
adj. 1 of minor importance; marginal. 2 of the periphery; on the fringe. 3 Anat. near the surface of the body, with special reference to the circulation and nervous system. 4 (of equipment) used with a computer etc. but not an integral part of it.
n. a peripheral device or piece of equipment. peripheral nervous system Anat. the nervous system outside the brain and spinal cord. peripherally adv.