1911 Encyclopædia Britannica/Co-optation

CO-OPTATION (from Lat. co-optare; less correctly “co-option”), the election to vacancies on a legislative, administrative or other body by the votes of the existing members of the body, instead of by an outside constituency. Such bodies may be purely co-optative, as the Royal Academy, or may be elective with power to add to the numbers by co-optation, as municipal corporations in England.