agreement, contract, treaty, convention, bargain, understanding, accord

These words have one thing in common, that is, they all mean “协议” to different extent. The subtle difference is going to be clarified here.

agreement : An arrangement between parties regarding a method of action; a covenant.

普通用词，含义最确定，泛指个人、团体或国家之间取得一致而达成的任何协议、协定或合同、契约等，可以是口头的，也可以是书面的。

contract ：An agreement between two or more parties, especially one that is written and enforceable by law.

侧重指双方或多方订立的具有法律效力的正式的书面合同或契约。

treaty ：A formal agreement between two or more states, as in reference to terms of peace or trade.

指国家之间经外交谈判后依照国际法签订的正式条约。

convention ：An agreement between states, sides, or military forces, especially an international agreement dealing with a specific subject, such as the treatment of prisoners of war.

比treaty更专门化，但不及treaty正式。也可指国家之间就有关事情签订的条约。

bargain ：An agreement establishing the terms of a sale or exchange of goods or services.

通常指商业交往中的购销合同。

understanding ：A compact implicit between two or more people or groups.

指不具约束力的非正式的协议。

accord ：A settlement of points at issue between nations.

多指国际间的非正式协议。