everyyoudaoicibaDictYouDict[every 词源字典]
every: [OE] Stripped down into its component parts, every means literally ‘ever each’. It was originally an Old English compound made up of ǣfre ‘ever’ and ǣlc ‘each’, in which basically the ‘ever’ was performing an emphasizing function; in modern English terms it signified something like ‘every single’, or, in colloquial American, ‘every which’. By late Old English times the two elements had fused to form a single word.
=> each, ever[every etymology, every origin, 英语词源]
every (adj.)youdaoicibaDictYouDict
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.