The phrase 또는 means or (else) between plain noun expressions:
- 커피 또는 홍차
coffee or (else) black tea
Another way to do the same thing is to link two words with the word 아니면 or:
- 커피 아니면 홍차
coffee or (else) black tea
At the beginning of a sentence, the phrase 또는 alsohas this contrastive idea, as in this sentence:
- 또는 음악회에도 가지 않았어요.
[Background: I haven’t been to a single movie this fall, hating them as I do.] Nor (on the other hand) have I been to any concerts either [and I do like concerts].
The word 아니면 can also begin a sentence, but has the meaning of Or else. . .:
-
- 지하철로 갈까요? 아니면, 택시로 갈까요?
Shall we take the subway? Or (else) shall we take a taxi?
- 지하철로 갈까요? 아니면, 택시로 갈까요?
또는, (이)나 and 아니면 thus all translate as or; but (이)나 and 아니면 accept either choice indifferently where 또는 excludes one of the choices, by contrasting it with the accepted choice.