the branch of trigonometry that deals with spherical triangles.
Origin of spherical trigonometry
First recorded in 1720–30
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
the branch of trigonometry concerned with the measurement of the angles and sides of spherical triangles
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012