a. Roman Law. To make an oral contract in the verbal form (of question and answer) necessary to give it legal validity. Said spec. of the party who asks the question., of an agreement, or of both contracting parties: To specify (something) as an essential part of the contract., of one of the parties to an agreement, or a person making an offer: To require or insist upon (something) as an essential condition. Now only with clause or inf. as obj., to make an express demand for something as a condition of agreement