1. Knowledge of the general structure of the Earth: Geognosy is the science dealing with the constituent parts of the Earth, its envelope of air and water, its crust, and the condition of its interior.

Geognosy is that part of geology which is concerned with the materials of the Earth's structure, and its general exterior and interior constitution.

In addition, geognosy is an earlier term for the science of the Earth. It is now replaced by "geology"..
2. Etymology: from Greek; literally "knowledge of the Earth".