A quorum is the minimum number of board members that have to be represented at a board meeting to conduct business (have a vote).  Unless a greater or lesser number is required by the bylaws, a quorum of a board consists of a majority of the number of board members in office immediately before the meeting begins.

Board members cannot vote or act by proxy, except for purposes of determining a quorum with respect to a particular proposal, and for purposes of casting a vote for or against a particular proposal, a board member may be considered to be present at a meeting and to vote if the board member has granted a signed directed proxy (see Index, proxy of director), but only if permitted in the bylaws.