treaty

Compared meaning: a formal agreement (noun).

比较义项：正式协议（尤指国家或团体之间）（名词）。

• accord

  Accord refers to a formal agreement reached through negotiation, often on political or diplomatic matters; it collocates with reach/sign an accord and sounds slightly less rigid than treaty.

  accord指经过谈判达成的正式协议，常用于政治或外交事务，常与reach/sign an accord搭配，语气比treaty略显不那么严格。

  The two countries finally reached a peace accord.

  两国终于达成了一项和平协定。

• treaty 本词

  Treaty is the most formal and legally binding term, typically a written document between national governments that is signed and often ratified; it is the standard word for major international agreements.

  treaty是最正式、最具法律约束力的词，通常指国家政府之间签署、并常需批准的书面文件，是表示重大国际协议的标准用词。

  The two nations signed a treaty to end the war.

  两国签署了一项条约以结束战争。

• pact

  Pact is the broadest term, covering agreements between countries, groups, or even individuals; it can sound informal or personal, unlike the strictly international, legalistic tone of treaty.

  pact是最宽泛的词，可用于国家、团体甚至个人之间的约定，语气可以显得非正式或私人化，不同于treaty那种严格的国际性、法律性语气。

  The two neighbors made a pact to share garden tools.

  两位邻居达成约定，共用园艺工具。

These three mean a formal agreement, but scope and formality differ. Treaty is most formal, a legally binding document between governments. Accord is reached through negotiation, often political or diplomatic. Pact is broadest, for countries, groups, or individuals. Not compared: accord's harmony sense.

这三个词都指正式达成的协议，但正式程度和适用范围不同：treaty最正式、通常需要签署甚至批准，专指国家间的书面条约；accord次之，强调通过谈判达成一致，多用于政治或外交场合；pact最宽泛，既可指国家间的正式条约，也可指个人或团体间随意的约定。这里不比较accord表示“和谐、一致”的其他用法（如in accord with）。