What term describes an understanding or agreement between governments?

The term that best describes an understanding or agreement between governments is "treaty." A treaty is a formal and legally binding agreement between two or more sovereign states. It typically outlines specific obligations, rights, and duties of the parties involved and is often ratified by the governments' respective legislative bodies, making it a critical component of international relations and diplomacy.

While "entente" refers to a less formal understanding or friendly agreement, where parties agree to cooperate or maintain peace without the strict binding nature of a treaty, it does not carry the same legal weight. An "alliance" typically refers to a formal agreement for mutual defense or cooperation during times of conflict, while a "coalition" usually pertains to a temporary alliance formed for a specific purpose or issue, such as during political campaigns or military operations. These terms may describe various forms of cooperation between governments, but a treaty specifically emphasizes a formal agreement with binding authority.