D defs.my
Entry 1 sense Webster, 1913

Dux

/dŭks/ · IPA /dʌks/
01 n. The scholastic name for the theme or subject of a fugue, the answer being called the comes, or companion.
  1. 1.
    The scholastic name for the theme or subject of a fugue, the answer being called the comes, or companion.(Mus.)