suffix *-tero-. Sense of "second" was detached from this word in Eng. (which uses second, from L.) and Ger. (zweiter, from zwei "two") to avoid ambiguity. In Scand., however, the second floor is still the "other" floor (cf. Swed. andra, Dan. anden). Phrase other world "world of idealism or fantasy, afterlife, spirit-land" is c.1200; hence otherworldliness (c.1834). The other woman "a woman with whom a man begins a love affair while he is already committed" is from 1855. The other day originally (1154) was "the next day;" later (c.1300) "yesterday;" and now, loosely, "a day or two ago" (1421). Phrase other half in reference to either the poor or the rich, is recorded from 1607.
"La moitié du monde ne sçayt comment l'aultre vit." [Rabelais, "Pantagruel," 1532]
O.E. æfre ælc "each of a group," lit. "ever each" (Chaucer's everich) with ever added for emphasis, as the word is still felt to need emphasis (Mod.Eng. every last ..., every single ..., etc.). Everybody is from c.1530, everyone is in M.E., everything is late 14c., everywhere is O.E. æfre
gehwær. The word everywhen is attested from 1843, but never caught on; neither did everyhow (1837). Everyman was the name of the leading character in a 15c. morality play. Slang phrase every Tom, Dick, and Harry dates from at least 1734, from common English given names.