peripheral pe·riph·er·al (pə-rĭf'ər-əl)
Related to, located in, or constituting an outer boundary or periphery.
Perceived or perceiving near the outer edges of the retina.
Of or relating to the surface or outer part of a body or organ; external.
Of, relating to, or being part of the peripheral nervous system.
Noun Computer Science An auxiliary device, such as a printer or modem, distinct from a computer's central processing unit and working memory, and often connected externally.
Any part that is separate from a computer's CPU, such as a printer, a keyboard, or a monitor.