Meaning of OR in English

1.conj. 1. a introducing the second of two alternatives (white or black). b introducing all but the first, or only the last, of any number of alternatives (white or grey or black; white, grey, or black).

2 (often prec. by either) introducing the only remaining possibility or choice given (take it or leave it; either come in or go out).

3 (prec. by whether) introducing the second part of an indirect question or conditional clause (ask him whether he was there or not; must go whether I like or dislike it).

4 introducing a synonym or explanation of a preceding word etc. (suffered from vertigo or giddiness).

5 introducing a significant afterthought (he must know - or is he bluffing?).

6 or else (run or you'll be late).

7 poet. each of two; either (or in the heart or in the head).

Phrases and idioms:

not A or B not A, and also not B. one or two (or two or three etc.) colloq. a few. or else

1. otherwise (do it now, or else you will have to do it tomorrow).

2 colloq. expressing a warning or threat (hand over the money or else). or rather introducing a rephrasing or qualification of a preceding statement etc. (he was there, or rather I heard that he was). or so (after a quantity or a number) or thereabouts (send me ten or so).

Etymology: reduced form of obs. other conj. (which superseded OE oththe or), of uncert. orig. 2. n. & adj. Heraldry

--n. a gold or yellow colour.

--adj. (usu. following noun) gold or yellow (a crescent or).

Etymology: F f. L aurum gold

Oxford English vocab.      Оксфордский английский словарь.