1. the process of becoming brighter or more luminous
2. the process of becoming more cheerful or hopeful

1. present participle of brighten; making or becoming brighter

Examples

• The brightening of the sky signaled dawn’s approach.
• There was a noticeable brightening in her mood after the good news.
• The brightening room made everyone feel more comfortable.
• His face showed a gradual brightening as he understood the joke.
• The brightening weather forecast lifted everyone’s spirits.
• She noticed the brightening of the colors as the sun emerged.
• The brightening prospects for the economy encouraged investors.