Duarchy
The Cyclopedic Law Dictionary · Walter A. Shumaker and George Foster Longsdorf; ed. James C. Cahill · 1922
The Cyclopedic Law Dictionary
A form of government where two reign jointly. DUAS UXORES EODEM TEMPORE HAbere non potest. It is not lawful to have two wives at one time.
Inst. 1. 10. 6; 1 Sharswood, Bl. Comm. 436.