Nonsolar

Nonsolar is a general adjective meaning not solar; not derived from or related to the Sun. In many technical domains it is used to distinguish processes, energy sources, or materials that do not rely on direct solar radiation. In energy discussions, nonsolar sources commonly include geothermal, nuclear, fossil fuels, and hydropower, though some depend on solar energy in a broader cycle. The term serves as a contrast to solar energy and is chosen for clarity when evaluating technologies, policies, or performance that do not depend on sunlight.

In astronomy and planetary science, nonsolar describes measurements or properties that differ from solar references. For example, nonsolar chemical abundances refer to element ratios that diverge from those found in the Sun, and nonsolar spectra describe light signatures not matching solar templates. The term also appears in discussions of exoplanets, circumstellar disks, and stellar populations when the Sun is used as a baseline.

Etymology and usage notes: formed from the prefix non- plus solar, from Latin sol, Sun. The term is widely understood in scientific writing but can be vague without context; more precise descriptors such as non-solar energy, non-solar radiation, or non-solar abundances are often preferred. See also solar.