APPUYING
Verb
appuying
present participle of appuy
Source: Wiktionary
APPUI
Ap`pui", n. Etym: [F., fr. L. ad + podium foothold, Gr.
Definition: A support or supporter; a stay; a prop. [Obs.]
If a be to climb trees that are of any great height, there would be
stays and appuies set to it. Holland.
Point d'appui. Etym: [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.
Source: Webster’s Unabridged Dictionary 1913 Edition