Term used in the German Residence Act (AufenthG). Citizens from non-EU countries generally require a residence title (or permit) to enter and stay in Germany. The German Residence Act is based on European regulations (EU Visa Code, among others) and distinguishes between residence permit, EU Blue Card, and temporary residence visa, as well as between settlement permit and permanent residence permit (EC).

Source: Bundesministerium des Innern (only available in German), Wikipedia, edited