tsar

Tsar ( or ; alternatively czar, tzar or csar) was a title used by Slavic monarchs. The term is derived from the Latin word caesar, which was intended to mean "emperor" in the European medieval sense of the term—a ruler with the same rank as a Roman emperor, holding it by the approval of another emperor or a supreme ecclesiastical official (the Pope or the Ecumenical Patriarch)—but was usually considered by Western Europeans to be equivalent to "king". It lends its name to a system of government, tsarist autocracy or tsarism.