Don (Spanish: [don]; Italian: [dɔn]; Portuguese: Dom [dõ], from Latin dominus, roughly 'Lord'), abbreviated as D., is an honorific prefix primarily used in Spain and the former Spanish Empire, Croatia, Italy, and Portugal and its former colonies.
Don, and dom, is derived from the Latin Dominus: a master of a household, a title with background from the Roman Republic in classical antiquity. With the abbreviated form having emerged as such in the Middle Ages, traditionally it is reserved for Catholic clergy and nobles, in addition to certain educational authorities and persons of distinction.
The female equivalent is Doña (Spanish: [ˈdoɲa]), Donna (Italian: [ˈdɔnna]), Romanian: Doamnă and Dona (Portuguese: [ˈdonɐ]) abbreviated D.ª, Da., or simply D. It is a common honorific reserved for women, such as the First Lady of Brazil. In Portuguese "Dona" tends to be less restricted in use to women than "Dom" is to men.