Anglicization of the Irish name Dorean. It may also be a derivative of Dora with the addition of the productive suffix -een, representing an Irish pet form. It peaked in popularity in the first half of the 20th century but has since fallen from favour.
Italian (Mònaco): nickname for someone of monkish habits or appearance, or an occupational name for a servant employed at a monastery, from Italian monaco ‘monk’ (from Greek monakhos ‘monk’, ‘solitary’). Monachos is also found as a Greek family name. Compare English Monk.