keystone

C1 · Advanced Countable noun Academic · Formal

n. the most important part of a plan, idea, or system that everything else depends on.

n. the central supporting element of a policy, system, or line of reasoning upon which all other parts depend.

“Trust is the keystone of any healthy relationship.”

“The right to free speech is often described as the keystone of a democratic society, supporting all other individual liberties.”

C2 · Proficiency Computing Technical

v. to change the shape of a projected image because the projector is at an angle.

v. to distort a projected image into a trapezoidal shape by projecting it onto a surface at a non-perpendicular angle.

“The image on the screen looked like a triangle because the projector was keystoning.”

“Modern digital projectors often include a feature to automatically correct keystoning when the device cannot be placed directly in front of the screen.”