spherograph

English

Etymology

sphero- +‎ -graph

Noun

spherograph (plural spherographs)

1. An instrument for facilitating the practical use of spherics in navigation and astronomy, constructed of two cardboards containing various circles, turning upon each other in such a manner that any possible spherical triangle may be readily found, and the measures of the parts read off.

Part or all of this entry has been imported from the 1913 edition of Webster’s Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.
(See the entry for “spherograph”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.)