/
ˈʌɪðə,
ˈiː-/
conj.
&
adv.
- used before the first of two (or occasionally more) alternatives specified (the other being introduced by ‘or’).
-
[adv., with neg.]
used to indicate a similarity or link with a statement just made.
▸moreover.
det.
&
pron.
one or the other of two people or things.
▸each of two.
Usage
In good English, it is important that either and or are correctly placed so that the structures following each word balance and mirror each other. Thus, sentences such as either I accompany you or I wait here and I'm going to buy either a new camera or a new video are correct, whereas sentences such as either I accompany you or John and I'm either going to buy a new camera or a video are not well balanced.
Etymology
OE ægther, contracted form of æg(e)hwæther, of Gmc origin; ult. rel. to aye2 and whether.