1. after a negative statement used as an intensive meaning something like `likewise' or `also'
- he isn't stupid, but he isn't exactly a genius either
- I don't know either
- if you don't order dessert I won't either
Sentences with either as an adverb:
- I don't like him and I don't like her either.
1. Introduces the first of two options, the second of which is introduced by "or".
- Either you eat your dinner or you go to your room.
1. Each of two. [from 9th c.]
2. One or the other of two. [from 14th c.]
3. (coordinating) Used before two or more not necessarily exclusive possibilities separated by "or" or sometimes by a comma.
- You'll either be early, late, or on time.
1. (obsolete) Both, each of two or more.
2. One or other of two people or things.