Meaning

adjective (used of count nouns) every one considered individually

adverb to or from every one of two or more (considered individually)

originFrom Middle English eche, elche, ilch, from Old English ǣlċ, contraction of ǣġhwelċ. Comparable to aye + alike. Compare Scots ilk, elk (“each, every”), Saterland Frisian älk (“each”), West Frisian elk, elts (“each”), Dutch elk (“each”), Low German elk, ellik (“each”), German Low German elk, elke (“each, every”), German jeglicher (“any”). By surface analysis, Old English ā + which.

Etymology from Wiktionary, CC BY-SA 3.0