every (adj.)
early 13c., contraction of Old English æfre ælc "each of a group," literally "ever each" (Chaucer's everich), from each with ever added for emphasis. The word still is felt to want emphasis; as in Modern English every last ..., every single ..., etc.

Also a pronoun to Chaucer, Shakespeare, Spenser. Compare everybody, everything, etc. The word everywhen is attested from 1843 but never caught on; neither did everyhow (1837). Slang phrase every Tom, Dick, and Harry "every man, everyone" dates from at least 1734, from common English given names.