UK:*UK and possibly other pronunciationsUK and possibly other pronunciations/ˈaɪðər/, /ˈiːðər/US:USA pronunciation: IPA and respellingUSA pronuncation: IPA/ˈiðɚ, ˈaɪðɚ/ ,USA pronunciation: respelling(ē′ᵺər, ī′ᵺər)

WordReference Collins English Usage © 2020
used as a determiner
You use either in front of the singular form of a countable noun to say that something is true about each of two people or things.
Many children don't resemble either parent.
In either case, Robert would never succeed.
‘either of’
Instead of using either, you can use either of with a plural noun. For example, instead of saying ‘Either answer is correct’, you can say ‘Either of the answers is correct’. There is no difference in meaning.
You could hear everything that was said in either of the rooms.
They didn't want either of their children to know about this.
You use either of in front of plural pronouns.
I don't know either of them very well.
He was better dressed than either of us.
Be careful
Don't use either without of in front of a plural noun or pronoun. Don't say, for example ‘He was better dressed than either us.’
Some people use a plural form of a verb after either of and a noun phrase. For example, instead of saying ‘I don’t think either of you is wrong', they say ‘I don’t think either of you are wrong'.
I'm surprised either of you are here.
This use is acceptable in conversation and in less formal writing, but in formal writing you should always use a singular form of a verb after either of.
Either of these interpretations is possible.
used in negative statements
You can use either or either of in a negative statement to emphasize that the statement applies to both of two things or people. For example, instead of saying about two people ‘I don’t like them', you can say ‘I don’t like either of them'.
She could not see either man.
There was no sound from either of the rooms.
‘Which one do you want – the red one or the blue one?’ – ‘I don’t want either.'
used to mean ‘each’
If there are things on either side of something or either end of something, they are on both sides or both ends.
There were trees on either side of the road.
There are toilets at either end of the train.
used as an adverb
When one negative statement follows another, you can put either at the end of the second one.
I can't play tennis and I can't play golf either.
‘I haven’t got that address.' – ‘No, I haven’t got it either.'
➜ See neither
➜ See nor
'either' also found in these entries:

Report an inappropriate ad.