Resident spy

A resident spy in the world of espionage is an agent operating within a foreign country for extended periods of time. A base of operations within a foreign country with which a resident spy may liaise is known as a "station" in English and a rezidentura (резиденту́ра, 'residency') in Russian. What the U.S. would call a "station chief", the head spy, is known as a rezident (резиде́нт) in Russian.