steradian

• Nom masculin désignant l'unité de mesure de l'angle solide dans le Système international d'unités, définie comme l'angle solide qui, ayant son sommet au centre d'une sphère, découpe sur la surface de celle-ci une aire égale au carré du rayon.

A noun referring to the SI unit of solid angle, defined as the solid angle subtended at the center of a sphere by an area on its surface equal to the square of the sphere's radius.

1. C2formalscientific

   The SI unit of solid angle, equal to the solid angle subtended at the center of a sphere by an area on its surface equal to the square of the sphere's radius.

   stéradian

   • The total solid angle of a sphere is 4π steradians.
   • The intensity of the light source was measured in lumens per steradian.
   • A full sphere contains approximately 12.57 steradians.