Definition of keystoning in English:

keystoning

noun

  • The action of giving something a trapezoidal shape; the result of this. Now chiefly Cinematography, Television, and Photography: the keystone effect; distortion arising from this.

Origin

1920s; earliest use found in U.S. Patents. From keystone + -ing.

Pronunciation

keystoning

/ˈkiːstəʊnɪŋ/