early 15c., "draw off (humors or spirits) as vapor," from Late Latin evaporatum, past participle of evaporare "disperse in vapor" (see evaporation). Intransitive sense by 1560s. Figurative use by 1610s. Related: Evaporated; evaporating. Evaporated milk (1870) is processed milk with some of the liquid removed by evaporation; it differs from condensed milk in being unsweetened.