A document adopted by an organization for its internal governance and its external dealings.
Much like the operating agreement for a Limited Liability Company, the Bylaws control the internal affairs of the Corporation. Bylaws describe how the Board of Directors of the Corporation is set up (how many Directors, how they are elected) and how the Corporation relates to other entities or people. Bylaws may describe the process for amendment. Bylaws may be amended by the Board of Directors or by the Shareholders.
It is important to revisit the bylaws regularly to make sure they reflect the way the Corporation is actually run.