A Locum tenens (Latin: "holding the place", i.e., "Placeholder") is a person who is temporarily fulfilling the duties and responsibilities of a particular office in the absence of a duly elected or appointed holder of that office. Such a person may be acting either as a substitute or as a deputy.

Thus, a physician who must be absent from his or her duties may have a locum tenens available to care for his or her patients. Likewise, a diocese whose bishop has retired or died may have a locum tenens until a new bishop can be installed. For example, Metropolitan Herman (Swaiko) of the Orthodox Church in America was the locum tenens of that church's Diocese of New England (in addition to his responsibilities as the Archbishop of Washington and New York) until the election of Bishop Nikon (Liolin) in October 2005.

Locum tenens is a cognate of the word lieutenant (which came to English through French).

See also Pro tem.

Latin phrases

Locum tenens | Местоблюститель патриаршего престола