Either
Either
ether, ther: Often in the sense still common, one or the other (1Ch 21:21; Mat 6:24, etc.), but also in the obsolete sense of both or each (Lev 10:1; 1Ki 7:15; Joh 19:18; Rev 22:2), or in place of (Revised Version) or (Luk 6:42; Luk 15:8; Phi 3:12; Jam 3:12).
Fuente: International Standard Bible Encyclopedia
Either
is a disjunctive particle. One of its uses is to distinguish things which exclude each other, or one of which can take the place of another. It is translated “either” in Mat 6:24; Mat 12:33; Luk 16:13; Act 17:21; 1Co 14:6. The RV rightly omits it in Luk 6:42, and translates it by “or” in Luk 15:8; Phi 3:12; Jam 3:12.
Note: The adverb enteuthen, denoting “hence,” is repeated in the phrase rendered “on either side,” (lit., “hence and hence”) in Joh 19:18. The RV of Rev 22:2 translates it “on this side,” distinguishing it from ekeithen, “on that side;” the AV, following another reading for the latter adverb, has “on either side.” See HENCE.