Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 43, § 55

Every order, ordinance, resolution and vote relative to the affairs of the city, adopted or passed by the city council, shall be presented to the mayor for his approval. If he approves it he shall sign it; if he disapproves it he shall return it, with his written objections, to the city council, which shall enter the objections at large on its records, and again consider it. If the city council, notwithstanding such disapproval of the mayor, shall again pass such order, ordinance, resolution or vote by a two thirds vote of all its members, it shall then be in force, but such vote shall not be taken for seven days after its return to the city council. Every such order, ordinance, resolution and vote shall be in force if not returned by the mayor within ten days after it has been presented to him. This section shall not apply to budgets submitted under section thirty-two of chapter forty-four or to appropriations by a city council under section thirty-three of said chapter.