Ascendant As*cend"ant, n. [F. ascendant, L. ascendens; p. pr. of ascendere.] 1. Ascent; height; elevation. [R.] Sciences that were then in their highest ascendant. --Temple. 2. (Astrol.) The horoscope, or that degree of the ecliptic which rises above the horizon at the moment of one's birth; supposed to have a commanding influence on a person's life and fortune. Note: Hence the phrases To be in the ascendant, to have commanding power or influence, and Lord of the ascendant, one who has possession of such power or influence; as, to rule, for a while, lord of the ascendant. --Burke. 3. Superiority, or commanding influence; ascendency; as, one man has the ascendant over another. Chievres had acquired over the mind of the young monarch the ascendant not only of a tutor, but of a parent. --Robertson. 4. An ancestor, or one who precedes in genealogy or degrees of kindred; a relative in the ascending line; a progenitor; -- opposed to descendant. --Ayliffe.