合約
contract
有明確的經濟後果，雙方幾乎沒有，如果有的話雙方或多方之間的協議，自由裁量權，以避免，通常是因為該協議是在法律上強制執行。合同可以採取多種形式的，不一定是書面的。
An agreement between two or more parties that has clear economic consequences that the parties have little, if any, discretion to avoid, usually because the agreement is enforceable at law. Contracts may take a variety of forms and need not be in writing.