1. A situation in which people share the same opinion: It was understood that any changes to the project plans required the agreement of the majority of those who were involved.
2. An arrangement, a contract, etc. by which all of those associated with something consent with what is to be done: The agreement expires in a month; so, Leon has to return the house under the terms of the deal he had with the original owner.

A written contract between two people who are about to marry, setting out the terms of possession of assets, treatment of future earnings, control of the property of each, and potential division if the marriage is later dissolved: An antenuptial agreement is fairly common if either or both parties have substantial assets, children from a previous marriage, potential large inheritances, or high incomes; which they feel should be provided for.

A written document signed by a couple who plan to marry: Jim's parents thought that he and his fiancée should have a prenuptial agreement made in which financial matters, including rights following a divorce or the death of one spouse, are legally detailed.

An arms control course of action in which two or more nations participate without any formal agreement having been made.