geognosy
The geological study of the Earth's structure and composition.
historical, obsolete, uncountable
Some writers divide Geology into two branches; 1. Geognosy, or Positive Geology, which embraces only the known facts of the science. 2. Geogony, or Speculative Geology, which attempts to point out the causes of those facts, and the inferences that result from them.
Where it comes from
From German Geognosie; coined by Abraham Gottlob Werner. By surface analysis, geo- + -gnosy.
Adapted from the Wiktionary entry geognosy (CC BY-SA 4.0).