late 14c., "western part" (of the heavens or the earth), from Old French occident (12c.) or directly from Latin occidentem (nominative occidens) "western sky, sunset, part of the sky in which the sun sets," noun use of adjective meaning "setting," from present participle of occidere "fall down, go down" (see occasion (n.)). As a geopolitical term, sometimes with a capital O, always somewhat imprecise.
With the definite article, the west; western countries; specifically, those countries lying to the west of Asia and of that part of eastern Europe now or formerly constituting in general European Turkey; Christendom. Various countries, as Russia, may be classed either in the Occident or in the Orient. [Century Dictionary, 1895]