Mass. Gen. Laws ch. 156B § 50
Subject to the provisions of section fifty-one, the directors and the president, treasurer and clerk shall hold office until the next annual meeting and until their respective successors are chosen and qualified, provided that the articles of organization may require the division of the directors into classes and prescribe the tenure of office of the several classes and the class of stock by which each class of directors shall be elected, but no class shall be elected for a shorter period than one year, or for a longer period than five years, and the term of office of at least one class shall expire in each year; and provided further that the articles of organization may require that the term of office of a director (or of an officer elected by stockholders) shall terminate upon the occurrence of an event or events specified in the articles of organization and may determine the manner, if any, by which any vacancy so created shall be filled.
Mass. Gen. Laws ch. 156B, § 50