Solid Geom. [irreg. f. Gr. στερε-ός solid + γωνία angle.] (See quot. 1881.)
1881. Halsted, Mensuration, 78. A steregon, the natural unit of solid angle, is the whole amount of solid angle about a point in space.
1883. W. Thomson, in Encycl. Brit., XVI. 25/2. [Adopts the word from Halstead, but uses it for ‘a plane solid angle,’ i.e., the amount of solid angle at the center which is subtended by the hemisphere].
