external (adj.)

"situated or being outside, pertaining to or connected with that which is outside," 1520s, from Latin exterior "outward, outer, exterior," comparative of exterus "on the outside, outward, outer, of another country, foreign," itself a comparative of ex "out of" (see ex-). As a noun, "outer surface or aspect" from 1590s.

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).