to give more light or colour to something, or to become lighter or more colourful
She opened the curtains to brighten the room.
A fresh coat of yellow paint will brighten the kitchen walls.
✦ formed from the adjective "bright" + the verb-forming suffix "-en" in Middle English, meaning “to make bright.”
to make someone feel happier or to become happier and more cheerful
The surprise gift from her friend quickly brightened her mood.
His face brightened when he heard the good news.
✦ figurative extension from the physical sense of adding light, recorded since the 17th century.
to make something give more light, look lighter, or show clearer, stronger color
He brightens the room by opening the curtains wide.
A fresh coat of white paint brightens the old kitchen instantly.
to become happier or make someone feel happier and more lively
Her face brightens whenever she sees her grandson.
The team’s mood brightens after hearing the good news.
