An agreement that is enforceable in law is

A contract is an agreement between two or more parties that the law will enforce, meaning that if one party fails to keep their promise, the other can take legal action to obtain a remedy such as compensation or performance. For an agreement to become a contract, it must generally contain several elements, including an offer, acceptance of that offer, and consideration (something of value exchanged by each side), along with the intention to create legal relations.

The other terms name only individual building blocks of a contract, not the finished, enforceable agreement itself. An offer is merely a proposal made by one party. A consideration is the value each party gives or promises to give. An acceptance is simply the agreement to the terms of an offer. None of these alone amounts to a legally enforceable agreement; they must combine, along with other requirements, to form a contract.

Examination reminder: think of offer, acceptance, and consideration as ingredients; the contract is the finished, legally binding agreement that results once these ingredients are properly combined.