What is Either ?
Either is adj, pron 1. one or the other You can use either computer it doesn’t matter which. I don’t like either of them. 2. each of two; both There are trees on either side of the road. Some people don’t take sugar in their coffee, some don’t take milk, and some don’t take either. they sat on either side of him one sat on each side of him (conj) either … or showing one of two possibilities Either you come here or I’ll come to see you. It’s either a fox or a wolf. You must do it either today or tomorrow. (adv) with a negative, or to make a statement stronger He isn’t Irish and he isn’t Scottish either. She doesn’t want to go, and I don’t want to go either. The report wasn’t on the TV news, and it wasn’t on the radio either.
source: Easier English, Student Dictionary Upper Intermediate Level