Oyer (law Fr., a hearing, from Lat. audire, to hear). When one party declares on or otherwise pleads a deed, and founds his claim or rests his defence upon it, he must generally make profert of it, or in other words must aver in his pleadings that he produces the said deed in court. In practice, under a system of written pleadings, the production does not take place unless demanded by the adversary party, which is done by serving a written notice that he craves oyer. The party who has made profert then regularly grants oyer by giving a copy of the instrument, and this enables the opposite party to set it forth in his subsequent pleadings, and raise upon it any question which he may think of service to him in the case. It is only in this way that the deed is spread upon the record. If a party who regularly should make profert is unable for any reason to produce the instrument, he should not make profert, but should set forth in his pleading the facts which excuse it; for if profert is made, oyer must be granted when demanded, or judgment may be entered up for the want of it.
Oyer is not requisite in the case of unsealed instruments, or records; but an executor or administrator who brings suit in his representative capacity must make profert of the letters which are the foundation of his right to sue.