1540s, "quality of being real," from French réalité and directly Medieval Latin realitatem (nominative realitas), from Late Latin realis (see real, adj.). Meaning "real existence, all that is real" is from 1640s; that of "the real state (of something)" is from 1680s. Sometimes 17c.-18c. also meaning "sincerity." Reality-based attested from 1960. Reality television from 1991.