What is "single-member district"

A single-member district or single-member constituency is an electoral district that returns one officeholder to a body with multiple members such as a legislature. This is also sometimes called single-winner voting or winner takes all. The alternative are multi-member districts, or the election of a body by the whole electorate voting as one constituency.

A number of voting systems use single-member districts, including plurality (first past the post), runoffs, instant-runoff voting (IRV), approval voting, range voting, Borda count, and Condorcet methods (such as the Minimax Condorcet, Schulze method, and Ranked Pairs). Of these, plurality and runoff voting are the most common.

In some countries, such as Australia and India, members of the lower house of parliament are elected from single-member districts; and members of the upper house are elected from multi-member districts.