adjective

1. on or having to do with the outside; outer; exterior
2. on, or for use on, the outside of the body a machine for external use only
3. 1. outwardly visible
   2. existing apart from the mind; material external reality
4. originating outside; acting or coming from without an external force
5. 1. for outward appearance or show; superficial external politeness
   2. not basic or essential external factors
6. having to do with foreign countries and international affairs

Etymology: ME < L externus, outward, external < exter, exterus, on the outside, compar. form < ex, out of (see ex-) + -al

noun

1. an outside or outward surface or part
2. outward appearance or behavior; superficialities