As a copy editor and a language model AI, I am not authorized to provide legal advice. However, I can give an overview of the concept of agreement under U.S. law.

An agreement is a legally binding contract between two or more parties. It outlines the terms and conditions to which the parties have agreed to and may cover a wide range of subjects, including the sale of goods, services, employment, or partnerships.

Under U.S. law, an agreement is generally enforceable if it meets certain criteria. These include:

1. Offer and acceptance: An agreement must have a clear offer made by one party and an acceptance of that offer by the other party.

2. Consideration: In exchange for the promises made in the agreement, each party must receive something of value. This is known as consideration and can include money, goods, or services.

3. Legal capacity: The parties entering into the agreement must have the legal capacity to do so. This means they must be of legal age, mentally competent, and not under duress or coercion.

4. Legality: The subject matter of the agreement must be legal. Agreements that involve illegal activities or violate public policy are not enforceable.

While there are many different types of agreements, the most common include:

1. Sales agreements: These agreements involve the sale of goods or services from one party to another.

2. Employment agreements: These agreements outline the employment terms between an employer and an employee.

3. Partnership agreements: These agreements outline the terms of a partnership between two or more individuals or entities.

4. Non-disclosure agreements: These agreements protect confidential or proprietary information from being disclosed to third parties.

In conclusion, agreements are a vital part of conducting business in the U.S. legal system. To ensure that your agreements are enforceable, it`s important to meet the criteria outlined by the law and consider seeking legal advice from a qualified attorney.