In Roman law. A leader or military commander. The commander of an army. Dig. 3, 2, 2, pr.
In feudal and old European law. Duke; a title of honor, or order of nobility. 1 Bl. Comm. 997; Crabb, Eng. Law, 236.
In later law. A military governor of a province. See Cod. 1, 27, 2. A military officer having charge of the borders or frontiers of the empire, called “dux limitis.’9 Cod. 1, 49, 1, pr. At this period, the word began to be used as a title of honor or dignity.