bright ‧ en /ˈbraɪtn/ BrE AmE verb
1 . MAKE LIGHTER [transitive] ( also brighten something ↔ up ) to make something lighter or brighter:
Use blonde highlights to brighten your hair.
The morning sunshine brightened up the room.
2 . MAKE MORE ATTRACTIVE [transitive] ( also brighten something ↔ up ) to make something more colourful or attractive:
She bought some flowers to brighten the room.
I want to brighten the place up a bit.
3 . MAKE MORE ENJOYABLE [transitive] ( also brighten something ↔ up ) to make something more enjoyable, exciting, or interesting:
His letter brightened my day.
I felt I needed something to brighten up my life.
4 . BECOME LIGHTER/BRIGHTER [intransitive] to shine more strongly, or become brighter in colour:
The stage lights brightened to reveal a street scene.
5 . BECOME SUNNY [intransitive] ( also brighten up ) if the weather brightens, the sun begins to shine and it becomes lighter:
The sky brightened after lunch.
Let’s hope the weather brightens up later.
It brightened up a bit in the afternoon.
6 . BECOME HAPPY [intransitive] ( also brighten up ) to become happier or more excited:
His eyes brightened when we started talking about money.
She brightened up a bit when she saw us.