peripheral /pəˈɹɪf(ə)ɹ(ə)l/adjective 5noun 2forms 3 adjective5 •On the periphery or boundary. •Related to or located in the peripheral nervous system.We have isolated the gene encoding the Schwann cell glycoprotein P0, the major structural protein of the peripheral myelin sheath. — 1988 •Beside the point. •Unimportant. •Auxiliary. noun2 •A peripheral device.Check your peripheral's manual for the information you'll need. — 1984 •Peripheral vision.We hailed a cab. The moment we got in, she stared at me with how-can-a-man-be-so-cruel eyes. I felt her glare, saw some of its fiery glow in my peripheral. The heat made me glance her way. — 2000 formsperipherals · more peripheral · most peripheral