Constituency

A constituency is any cohesive corporate unit or body bound by shared structures, goals or loyalty. It can be used to describe a business's customer base and shareholders, or a charity's donors or those it serves. The most common meaning of constituency occurs in politics and means either the group of people from whom an individual or organization hopes to attract support, or the group of people or geographical area that a particular elected representative or group of elected representatives represents. The rest of this article deals with this sense of constituency.

When used specifically, a constituency usually refers to the group or area from which voters in an election are drawn. Depending on the electoral system being used, a constituency may elect one or more members. For instance, in the United Kingdom, House of Commons Parliamentary constituencies each elect one Member of Parliament using a first past the post system (though some used to elect more than one), while the larger European Parliament constituencies each elect a number of Members of the European Parliament (see 'Regions of England').

In Namibia and in Canton of St. Gallen in Switzerland, it is also used as an administrative division.

A marginal constituency is one where the margin between the expected voting for the major parties in an election is slim. In United Kingdom general elections, the voting in a relatively small number of marginal constituencies usually determines the outcome of the entire election. Currently the most marginal UK constituency is Crawley in West Sussex where Labour have a majority of 37 votes over The Conservative Party.