Solid earth refers to "the earth beneath our feet" or terra firma, the planet's solid surface and its interior.[1]: v [2]: 1 It excludes the Earth's fluid envelopes, the atmosphere and hydrosphere (but includes the ocean basin), as well as the biosphere and interactions with the Sun.
Solid-earth science refers to the corresponding methods of study, a subset of Earth sciences, predominantly geophysics and geology, excluding aeronomy, atmospheric sciences, oceanography, hydrology, and ecology.