noun
duchy; dukedom; principality
A territory ruled by a duke or prince; used in historical and modern contexts (e.g., モナコ公国).
モナコ公国はフランスの南東に位置する。
The Principality of Monaco is located in southeastern France.
中世ヨーロッパには多くの公国が存在した。
Many duchies existed in medieval Europe.