every (adj.) Look up every at Dictionary.com
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.

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 dates from at least 1734, from common English given names.