Brightness
Obhāsa Sutta  (AN 4:144)

“There are these four types of brightness. Which four? The brightness of the sun, the brightness of the moon, the brightness of fire, and the brightness of discernment. These are the four types of brightness. And of these four types of brightness, the foremost is the brightness of discernment.”

See also: Dhp 59; Dhp 387; Iti 59