noun. The flash of light which passes over the surface of the melted metal when lead containing silver is assayed on a cupel in a muffle.

noun. In dyeing, same as blooming, 2.

verb. Present participle of brighten.

noun. An instance of becoming brighter

"Had this been one of her plays, Thomas would now return, throwing the door wide, his expression brightening on seeing her still in his bed."

enlightening  frightening  heightening  lightening  lightning  

brighten