Parliamentary boroughs are boroughs that are entitled to representation in a Parliament. The term came into use in the 19th century in the United Kingdom, when certain boroughs were disenfranchised, becoming merely municipal boroughs. The two sets of boroughs were detached further by being allowed to have different boundaries. Originally many parliamentary boroughs were multi-member constituencies, but the Reform Acts eventually divided them all into single-member divisions. Divisions of parliamentary boroughs eventually became known as borough constituencies.
