What is "spherics"

Spherics \Spher"ics\, n. (Math.) The doctrine of the sphere; the science of the properties and relations of the circles, figures, and other magnitudes of a sphere, produced by planes intersecting it; spherical geometry and trigonometry.

n. 1 (context mathematics English) The part of geometry and trigonometry that deals with spheres. 2 (alternative form of sferics lang= en)