Source : Webster's Revised Unabridged Dictionary (1913)

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.

Point d'appui \Point` d'ap`pui"\ [F.] (Mil.)
   See under {Appui}.

Appui \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.