A by-election is a special election held to fill a vacant seat in Parliament, a provincial legislature, or municipal council between regular general elections. Vacancies occur when a member dies, resigns, is removed from office, or becomes disqualified. By-elections are held in only the affected riding or ward, not across the entire jurisdiction. They receive significant attention as tests of current political sentiment and government popularity. The new member serves only the remainder of the original term. Municipal by-elections fill councillor seats mid-term, ensuring continuous representation for affected wards until the next scheduled municipal election.