What is the meaning of Point_d'appui?

A given point or body upon which troops are formed, or by which they are marched in line or column.

An advantageous defensive support; a foothold.

A specific note, chord, or phrase that serves as a stable reference point within a piece of music, providing harmonic or melodic grounding.

A focal point; a centre of attention.

An anchor point against which one pushes.

Source: wiktionary.org