So what is a treaty and what other terms might be used in place of it? The term "treaty" has regularly been used as a generic term embracing all instruments binding at international law concluded between international entities, regardless of their formal designation. There are no consistent rules as to when a state practice employs the terms "treaty" as a title for an international instrument. The term ‘charter’ is used for particularly formal and solemn instruments, such as the treaty founding an international organization. The generic use of the term "convention" embraces many international agreements, in the same way the generic term "treaty“ does. In a more specific sense, the term “convention” term is generally used for formal multilateral treaties open for participation by the international community as a whole, or by a large number of states.
Final Acts, Protocols and Declarations differ from treaties. A "Final Act" designates a document that is a formal statement or summary of the proceedings of an international conference. It usually will list any treaties as a result of the conference along with any resolutions. Note that any treaties produced through a conference would still need to go through the ratification procedure to become binding.
The term "protocol" is used for agreements less formal than those entitled "treaty" or "convention.“
The term “declaration” is often deliberately chosen to indicate that the parties do not intend to create binding obligations but merely want to declare certain aspirations. This varies, however, so you need to establish in each individual case whether the parties intended to create binding obligations.
Non-US treaties can be a bit more difficult to find. There is no one central place where you can find all treaties. There are many treaties that are simply impossible to find. If you are lucky, a treaty may have been deposited with the UN or another Inter-governmental Organization. Every UN member nation is supposed to deposit the text of its treaties with the Secretariat who then publishes them in the United Nations Treaty Series (UNTS).
US Treaty Research CALI Lesson by 