proportional representation 
(abbreviation PR)
noun [mass noun]
An electoral system in which parties gain seats in proportion to the number of votes cast for them.The only solution that will solve all the list problems is to switch to the single transferable vote system of proportional representation....
- Unionists clarified the electoral system by abolishing proportional representation in 1929.
- Such a slate is required under the country's electoral system of proportional representation.