Either and any

Either means one or the other of two. Note that either is followed by a singular noun.

Either answer is correct.

Either method leads to the same result.

Either cannot be used for numbers greater than two. Instead, we use any.

Compare:

You can take either of these books. (There are just two books.)

You can take any of these shirts. (There are more than two shirts.)

Each and either

Each refers to every one of two or more things or persons taken separately and individually.

They gave each of their four daughters a dress.

The four daughters each received a dress.

Either can be used after not.

I don’t like Mary and I don’t like her sister either. (= I dislike both of them.)

Alice isn’t here. Peter isn’t here either. (= Neither of them is here.)

Either …or

The correlative either…or is used to introduce one of two alternatives.

He must be either sad or angry.

We must either go now or wait till he returns.

Every

Every is used to refer to all or each one of a group without exception.

I enjoyed every minute of the program.

I have seen every movie directed by Spielberg.