An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) Situated, placed, or lying face to face with something else or each other, or in corresponding positions with relation to an intervening line, space, or thing: opposite ends of a room (Dictionary.com).
2) Contrary or radically different in some respect common to both, as in nature, qualities, direction, result, or significance; opposed (Dictionary.com).
3) An → antonym.

M.E., from M.Fr., from L. oppositus, p.p. of opponere, → opposition.

1) Ru-be-ru "face to face," → surface.
2) Pârun, short for pâdrun, from pâd-, → counter, + -run "side, direction" (as in birun, darun, vârun), → out.
3) Pâdcem, → antonym.