The term for the natural phenomenon of a rainbow is "optical and meteorological phenomenon." Rainbows occur when sunlight refracts, reflects, and disperses in water droplets, resulting in a spectrum of light appearing in the sky. Typically, a rainbow forms when raindrops are present, and sunlight shines from behind the observer at a low angle. The result is a circular arc of colors, usually seen when the sun is shining while it’s raining. The seven main colors of a rainbow are red, orange, yellow, green, blue, indigo, and violet, often remembered by the acronym ROYGBIV.