or
basic uses
You use or when you are mentioning two or more alternatives or possibilities. You use or to link words, phrases, or clauses.
Would you like some coffee or tea, Dr Floyd?
It is better to delay planting if the ground is very wet or frosty.
Do you want to go to the beach or spend time at home?
used with negative words
You use or instead of ‘and’ after using a negative word. For example, say ‘I do not like coffee or tea’. Don't say ‘I do not like coffee and tea’.
The situation is not fair on the children or their parents.
It is not poisonous and will not harm any animals or birds.
The house is not large or glamorous.
verb agreement
When you link two or more nouns using or, you use a plural verb after plural countable nouns, and a singular verb after singular countable or uncountable nouns.
Even minor changes or developments were reported in the press.
If your son or daughter is failing at school, it is no use being angry.
‘either ... or’
You use either with or when you are mentioning two alternatives and you want to say that no other alternatives are possible. Either goes in front of the first alternative and or goes in front of the second one.
Replace it with a broadband access device, either rented or costing around $500.
➜ See either ... or
After neither, you usually use nor.
He speaks neither English nor German.
➜ See neither ... nor
linking more than two items
When you are linking more than two items, you usually only put or in front of the last one. After each of the others you put a comma. Often the comma is omitted in front of or.
Flights leave from Heathrow, Manchester, Gatwick, or Glasgow.
Students are asked to take another course in English, science or mathematics.
beginning a sentence with ‘or’
You don't normally put or at the beginning of a sentence, but you can sometimes do so when you are reporting what someone says or thinks.
I may go home and have a steak. Or I may have some spaghetti.
used for correcting
You can use or when you are correcting a mistake you have made, or when you think of a better way of saying something.
We were considered by the others to be mad, or at least very strange.