- 1 used to introduce another possibility Is your sister older or younger than you? Are you coming or not? Is it a boy or a girl? It can be black, white or grey. compare either… or…
- 2 used in negative sentences when mentioning two or more things He can't read or write. There are people without homes, jobs or family. compare neither… nor…
- 3 (also or else) used to warn or advise somebody that something bad could happen; otherwise Turn the heat down or it'll burn.
- 4 used between two numbers to show approximately how many There were six or seven of us there.
- 5 used to introduce a word or phrase that explains or means the same as another geology, or the science of the earth’s crust It weighs a kilo, or just over two pounds.
- 6 used to say why something must be true He must like her, or he wouldn't keep calling her.
- 7 used to introduce a contrasting idea He was lying—or was he? Word Origin Middle English: a reduced form of the obsolete conjunction other (which superseded Old English oththe ‘or’), of uncertain ultimate origin.Idioms about It'll cost €100 or so.
(informal) used when you are not exactly sure about a person, thing or place He's a factory supervisor or something. ‘Who said so?’ ‘Oh, somebody or other. I can't remember who it was.’