"account of some happening," early 13c., "narrative of important events or celebrated persons of the past," from Old French estorie, from Late Latin storia and Latin historia "history, account, tale, story" (see history). Meaning "recital of true events" first recorded late 14c.; sense of "narrative of fictitious events meant to entertain" is from c.1500. Not differentiated from history till 1500s. As a euphemism for "a lie" it dates from 1690s. Meaning "newspaper article" is from 1892. Story-teller is from 1709. Story-line first attested 1941. That's another story "that requires different treatment" is attested from 1818. Story of my life "sad truth" first recorded 1938.
"floor of a building," c.1400, from Anglo-Latin historia "floor of a building" (c.1200), also "picture," from Latin historia (see history). Perhaps so called because the fronts of buildings in the Middle Ages often were decorated with rows of painted windows.