Mixed-member proportional representation
Mixed-member proportional representation (often referred to as "MMP") is an electoral system used in Germany and in many  English-speaking countries. It is often thought of as a proportional representation system.  In the United Kingdom, MMP is often referred to as the "additional member system" (or "AMS").  It is used to select the German Bundestag in Germany and is used in parliaments and other elections in various English-speaking countries.