Late 16th century; earliest use found in Henry Lyte (1529–1607), botanist and antiquary. From post-classical Latin ros solis the plant sundew from classical Latin rōs dew + sōlis, genitive of sōl sun, perhaps after Dutch zondauw, †sondauw. Compare French rossolis, Catalan resolis sweet alcoholic liqueur, Spanish rosoli liqueur (originally) made from the sundew, Italian †rosolì a kind of sweet liqueur, and also Dutch rossolis sundew, liqueur.