1590s, in fresco, literally "in fresh," with a sense of "painted on fresh mortar or plaster," from Italian fresco "cool, fresh," as a noun "coolness, fresh air," from Old High German frisc, from Proto-Germanic *friskaz (see fresh (adj.1)). As a verb from 1849. Related: Frescoed. In 17c.-18c. it also could mean "coolness, shade."