Merriam-Webster Collegiate Dictionary - ascendant

 I. noun  also ascendent  Etymology: Middle English ascendent, from Medieval Latin ascendent-, ascendens, from Latin, present participle of ascendere  Date: 14th century  1. the point of the ecliptic or degree of the zodiac that rises above the eastern horizon at any moment  2. a state or position of dominant power or importance  3. a lineal or collateral relative in the ascending line  II. adjective  also ascendent  Date: 1591  1.  a. moving upward ; rising  b. directed upward an ~ stem  2.  a. superior  b. dominant 1a  • ~ly adverb