Pocket borough
Defined in 1 dictionary — Black's (1910)
Black's Law Dictionary
Henry Campbell Black, M.A. · 1910
A term formerly used in English politics to describe a borough entitled to send a representative to parliament, in which a single individual, either as the principal landlord or by reason of other predominating influence, could entirely control the election and insure the return of the candidate whom he should nominate.
Defined under Borough in Black's Law Dictionary.