protective secretion of the mucous membranes; in the gut it lubricates the passage of food and protects the epithelial cells; in the nose and throat and lungs it can make it difficult for bacteria to penetrate the body through the epithelium
(computer science) electronic equipment connected by cable to the CPU of a computer; "disk drives and printers are important peripherals"
on or near an edge or constituting an outer boundary; the outer area; "Russia's peripheral provinces"; "peripheral suburbs"
related to the key issue but not of central importance; "a peripheral interest"; "energy is far from a peripheral issue in the economy"; "peripheral issues"
outward features; "he enjoyed the solemn externals of religion"
happening or arising or located outside or beyond some limits or especially surface; "the external auditory canal"; "external pressures"
purely outward or superficial; "external composure"; "an external concern for reputation"- A.R.Gurney,Jr.
from or between other countries; "external commerce"; "international trade"; "developing nations need outside help"
coming from the outside; "extraneous light in the camera spoiled the photograph"; "relying upon an extraneous income"; "disdaining outside pressure groups"
not forming an essential part of a thing or arising or originating from the outside; "extrinsic evidence"; "an extrinsic feature of the new building"; "that style is something extrinsic to the subject"; "looking for extrinsic aid"