a document issued by the Head of a State, granting recognition to a foreign consul appointed thereto

An exequatur is a patent which a head of state issues to a foreign consul which guarantees the consul's rights and privileges of the office and ensures recognition in the state to which the consul is appointed to exercise such powers. If a consul is not appointed by commission, the consul receives no exequatur; the government will usually provide some other means to recognize the consul. The exequatur may be withdrawn, but in practice, where a consul is obnoxious, an opportunity is afforded to his government to recall him.