Spherical Excess

The difference between the sum of the angles $A$, $B$, and $C$ of a Spherical Triangle and $\pi$ radians (180°),

$$E=A+B+C-\pi.$$

See also Angular Defect, Descartes Total Angular Defect, Girard's Spherical Excess Formula, L'Huilier's Theorem, Spherical Triangle