Constitution is a an aggregate of fundamental principles or established precedents that constitute the legal basis of a polity, organisation or other types of entity and commonly determines how that entity is to be governed.
Veto is a the political right to disapprove of the process of a decision, a law etc. An invocation of that right.
Bill of Rights a formal statement of the fundamental rights of the people of the United states, incorporated in the Constitution as Amendment 1-10, and in all state constitutions.
Ratify is the confirmation or adoption of an act that has already been performed.