Sire

Sire is an archaic respectful Forms of [address in the United Kingdom|form of address] to reigning kings in Europe. In French and other languages it is less archaic and relatively more current. In Belgium, the king is addressed as "Sire..." in both Dutch and French.
The words "sire" and "sir", as well as the French "(mon)sieur", the Spanish "señor", and the Portuguese "senhor", share a common etymological origin, all ultimately being related to the Latin senior. The female equivalent form of address is dame or dam.