Main Entry: ¹ei·ther

Pronunciation: \ˈē-thər also ˈī-\

Function: adjective

Etymology: Middle English, from Old English ǣghwæther both, each, from ā always + ge-, collective prefix + hwæther which of two, whether — more at aye, co-

Date: before 12th century

1 : being the one and the other of two : each <flowers blooming on either side of the walk> <plays either instrument well>
2 : being the one or the other of two <take either road>