1. A branch of atmospheric physics or physical meteorology in which optical phenomena occurring in the atmosphere are described and explained.
2. The study of the optical characteristics of the atmosphere or products of atmospheric processes.

The term is usually confined to visible and near visible radiation; however, unlike meteorological optics, it routinely includes temporal and spatial resolutions beyond those discernible with the naked eye.

Meteorological optics is that part of atmospheric optics concerned with the study of patterns observable with the naked eye.

This restriction is often relaxed slightly to allow the use of simple aids; such as, binoculars or a polarizing filter.

Topics included in meteorological optics are sky color, mirages, rainbows, halos, glories, coronas, and shines.