What does "brightening" mean?

An instance of becoming brighter.

Brightening

Common synonyms include: aurora, break of day, brighten, brightening treatment, brightness enhancement, brightness increase.

noun, verb

noun, verb ·3 syllables ·Moderate ·College level

Noun

Verb

1
present participle and gerund of brighten form-of, gerund, participle, present

"Brightening teeth is a multimillion- or multibillion-dollar industry."