Definition
An unfilled board seat, created by resignation, removal, or a lack of candidates, that must be filled per the bylaws.
A board vacancy occurs when a director's seat becomes empty — through resignation, removal, or simply no one running for an open seat. The bylaws dictate how vacancies are filled.
Commonly, the remaining directors appoint a replacement to serve until the next election, though some documents require a special membership vote. Filling vacancies promptly keeps the board at working strength and able to reach quorum.