The minimum number of directors who must be present at a directors meeting, or shares of stock that must be represented by stockholders at a stockholders meeting in order to conduct business or take action.

Used substantively, quorum signifies the number of persons belonging to a legislative assembly, a corporation, society, or other body, required to transact business; there is a difference between an act done by a definite number of persons, and one performed by an indefinite number: in the first case a majority is required to constitute a quorum, unless the law expressly directs that another number may make one; in the latter case any number who may be present may act, the majority of those present having, as in other cases, the right to act. Sometimes the law requires a greater number than a bare majority to form a quorum, in such case no quorum is present until such a number convene.

When an authority is confided to several persons for a private purpose, all must join in the act, unless otherwise authorized.