Something promised , given , or done that has the effect of making an agreement a legally enforceable contract 对价,承诺被允诺、提供或做成的事物,它能使一项协议成为具有法律效力的契约
Clear proof of a doctor ' s promise of specific medical results may give rise to an enforceable contract (就医生所为达到特定医疗成效的意思表示,倘若有明确的证据,此一契约系属一可强制履行的契约。 )