Appui

Ap·pui

Appui

n.
  1. A support or supporter; a stay; a prop. [Obs.]
    If a vine be to climb trees that are of any great height, there would be stays and appuies set to it.
  2. The mutual bearing or support of the hand of the rider and the mouth of the horse through the bit and bridle. (Man.)

Phrases & Compounds
Point d'appui
A given point or body, upon which troops are formed, or by which are marched in line or column.