Appui

||Ap`pui" (?), n. (Man.) The mutual bearing or support of the hand of the rider and the mouth of the horse through the bit and bridle. -- Point d'appui (?), any point of support or basis of operations, as a rallying point.

||Ap`pui" (?), n. [F., fr. L. ad + podium foothold, Gr. ?, dim. of ?, ?, foot.] 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.
Holland.

Point d'appui (?). [F., a point of support.] (Mil.) (a) A given point or body, upon which troops are formed, or by which are marched in line or column. (b) An advantageous defensive support, as a castle, morass, wood, declivity, etc.