Eitheris adeterminer, a pronoun, an adverb or a conjunction.
We can pronounceeither/ˈaɪðə(r)/or/ˈi:ðə(r)/.
Eitheras a determiner
Eitherreferring to two choices or possibilities
We can useeitheras a determiner before a noun to talk about two choices or possibilities. The noun that followseithermust be a singular countable noun:
Personally, I don’t likeeitherjacket.
Not: …I don’t like either jackets.
Either restaurant will be okay, as they both serve vegetarian food.(Itdoesn’t matter which of the two restaurants you go to.)
Either of
Eithermust be followed byofif we use it beforethe,these, thoseor possessives (my, your) with a plural noun:
Eitherof thechildren can come with us; we don’t mind which.
I don’t wanteither of myparents to know I’ve lost my job.
Not:I don’t want either my parents…
Eithermeaning ‘both’
Eitheras a determiner before a singular countable noun can mean ‘both’:
There were shops oneitherside of the street.
Eitheras a pronoun
We can useeitheras a pronoun:
A:Which sweater do you like, the green one or the blue one?
B:I don’t likeeither. (I don’t like the green one and I don’t like the blue one.)
A:What colour paper do you want, white or cream?
B:Either.It doesn’t matter.
Eitheras an adverb
We can useeitheras an adverb after a negative verb:
It was a really nice hotel, and it wasn’tvery expensiveeither.
She doesn’t like eggs and she doesn’tlike fisheither.
Eitheras a conjunction
We can useeitherwithoras a conjunction to connect two clauses:
Eitherwe go by trainorwe rent a car. Which do you prefer?