1. The electrical processes occurring in the lower atmosphere, including both the intense local electrification accompanying storms and the much weaker fair-weather electrical activity over the entire globe produced by the electrified storms continuously in progress.
2. The study of electrical processes occurring within the atmosphere.
3. Electrical phenomena, regarded collectively, that occur in the earth's atmosphere.

These phenomena include not only such striking manifestations as lightning and St. Elmo's fire, but also less noticeable but more ubiquitous effects; such as, atmospheric ionization, the air–earth currents, and other quiescent electrical processes.

The existence of separated electric charges in the atmosphere is a consequence of many minor processes; such as, spray electrification, dust electrification, etc. and a few major processes including, cosmic-ray ionization, radioactive-particle ionization, and thunderstorm electrification.

The maintenance of the prevailing atmospheric electric field is now widely believed to be due to thunderstorm effects.