Periphery

Generally, a periphery is a boundary or outer part of any space or body. It is derived from the Greek word , meaning a circumference or outer surface.

 In biology, the periphery of the body is the part that is away from the central or core regions.
 For example, the peripheral nervous system is distinct from the central nervous system.
 See also peripheral membrane protein.

 Peripheral vision is that part of visual perception that occurs in the periphery, i.e., near the edges, of the field of view.

 A computer peripheral is added to a host computer in order to expand its abilities.

For peripheral submanifolds in mathematics, see boundary parallel.

 The Periphery includes nations that are not core countries -  capitalist or industrialized nations. See Immanuel Wallerstein, Third World.

 The 13 peripheries of Greece are subnational subdivisions of that country, equivalent to regions.

 In the fictional universe of BattleTech, the Periphery is the region of interstellar space.