The Basque señoríos were medieval hereditary land titles over an area called señorío ( Lordship ), recognized by a king to former basque chieftains in relation to the concept of manorialism in exchange for sworn allegiance. The Basque term is jaurerria (pronounced [xauˈɾeria]), means "lord's country" and usually relates to the señoríos of the Basque Country. Either term frequently refers to the most important of these, the Bizkaiko Jaurerria or Señorío de Vizcaya (Lordship of Biscay) as it is known in Spanish. Most other Basque jauerriak were much smaller, such as the Oñatiko Jaurerria (Señorío de Oñate).

This title conferred considerable powers into the hands of the Lord of Vizcaya which in other area were directly controlled by the king. A señor was the judicial and military high authority, was entitled to rule directly without referring to the king, had the power to appoint civil servants and was entitled to collect taxes.