An agreement is a concept that includes any arrangement or understanding between two or more parties about their rights and responsibilities with respect to one another.
In order to reach an agreement, parties need only come to a common understanding as to their relative rights and responsibilities, what is often termed a “meeting of the minds.”
An agreement may simply involve one party accepting another party's offer. Since this scenario does not involve consideration, it is not a contract. Other common examples of agreements which are not contracts include gentlemen’s agreements and unlicensed betting pools. The key element to all non-contract agreements is that they are not legally enforceable.
The primary benefit of an agreement that does not meet the criteria of a contract is that it is inherently informal. Where the agreeing parties have a longstanding relationship and share a considerable degree of trust, the use of a non-contract agreement can save time and allow for more flexibility in the fulfillment of the agreed-upon obligations.