[pe.riph.er.al] adj (1808) 1: of, relating to, involving, or forming a periphery or surface part
2: of, relating to, or being part of the peripheral nervous system "~ nerves"
3: of, relating to, or being the outer part of the field of vision "good ~ vision"
4: auxiliary, supplementary "~ equipment"; also: of or relating to computer peripherals -- pe.riph.er.al.ly adv
[2]peripheral n (1966): a device connected to a computer to provide communication (as input and output) or auxiliary functions (as additional storage)