What does "either" mean?

Either: Each of two; the one and the other; both; -- formerly, also, each of any number. His flowing hair In curls on either cheek played. Milton. On either side . . . was there the tree of life. Rev. xxii.

Additional senses

  1. 2.The extreme right and left of either army never engaged. Jowett (Thucyd).
  2. 3.precedes two, or more, coördinate words or phrases, and is introductory to an alternative. It is correlative to or. Either he is talking, or he is pursuing, or he is in a journey, or peradventure he sleepeth. 1 Kings xviii.
  3. 4.Few writers hesitate to use either in what is called a triple alternative; such as, We must either stay where we are, proceed, or recede. Latham. Note: Either was formerly sometimes used without any correlation, and where we should now use or. Can the fig tree, my brethren, bear olive berries either a vine, figs James iii. 12.

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