Peripheral
Peripheral , adjective
1.
Of or pertaining to a periphery; constituting a periphery; peripheric.
2.
(Anatomy) External; away from the center; on or near the surface; as, the peripheral portion of the nervous system.
3.
Pertaining to minor, unimportant, superficial, or irrelevant aspects of the matter in question; as, peripheral issues are dealt with in the appendix.