Airglow (or nightglow) is the glow of a planet's atmosphere. Earth has a faint airglow, from work function, chemistry, and the effects of cosmic rays, which means none of the night sky is totally dark even when starlight and the effects of the Sun on the interplanetary medium are taken into account. The auroras are some of the same thing, but the term aurora refers to a frequent, relatively bright glow around the poles whereas the term airglow refers to the effects that take place throughout the night sky.
Airglow affects and limits observation from the ground, giving space telescopes an advantage, and motivating optics to mitigate the effects.
OH airglow is emission from hydroxyl in the atmosphere.