/ikˈstərnl/
Adjective
1. Outside of something. (wiktionary.org)
2. Happening or arising or located outside or beyond some limits or especially surface. (wordnetweb.princeton.edu)
3. Relating to or denoting a medicine or similar substance for use on the outside of the body. (Google Dictionary)
Noun
1. The outward features of something. (Google Dictionary)
2. Features which are only superficial; inessentials. (Google Dictionary)
Word origin: From Middle French externe or directly from Latin externus “outside, outward” (from exterus) + -al