An official recognition by a government of a consul or other representative of a foreign state, authorizing them to exercise office.
（驻在国发给外国领事、代理人或其他代表的）许可证书；领事认可证书
Origin
Latin, literally 'let him or her perform'.
Definition of exequatur in US English:
exequatur
nounˌeksəˈkwādər
An official recognition by a government of a consul, agent, or other representative of a foreign state, authorizing them to exercise the duties of office.