A single-member district or constituency is an electoral district represented by a single officeholder. It contrasts with a multi-member district, which is represented by multiple officeholders.
In some countries, such as Australia and India, members of the lower house of parliament are elected from single-member districts, while members of the upper house are elected from multi-member districts. In some countries, such as Singapore, members of parliament are elected from both single-member and multi-member districts.