Rainbow
(Section 3.2.3.5)Definition: Rainbow: A group of concentric arcs with colours ranging from violet to red, produced on a “screen” of water drops (raindrops, or droplets of drizzle or fog) in the atmosphere by light from the Sun or Moon.
This phenomenon is mainly due to refraction and reflection of light. When rainbows are produced by the Sun, their colours are usually brilliant, and when produced by the Moon (“moonbow”), their colours are much weaker or sometimes absent.