1. [n]  someone from whom you are descended (but usually more remote that a grandparent)
2. [n]  position or state of being dominant or in control; "that idea was in the ascendant"
3. [adj]  most powerful or important or influential; "the economically ascendant class"; "D-day is considered the dominating event of the war in Europe"
4. [adj]  tending or directed upward; "rooted and ascendant strength like that of foliage"- John Ruskin

ASCENDENT is a 9 letter word that starts with A.