1. the external boundary of any surface or area.
2. the external surface of a body.
3. the edge or outskirts, as of a city or urban area.
4. the relatively minor, irrelevant, or superficial aspects of the subject in question: The preliminary research did not, of course, take me beyond the periphery of my problem.
5. Anatomy. the area in which nerves end.
1350–1400; < LL peripherīa < Gk periphéreia circumference, lit., a bearing round, equiv. to peri- peri- + phér(ein) to bear 1 + -eia -y 3 ; r. ME periferie < ML periferīa, var. sp. of LL peripherīa