- 1 [intransitive, transitive] to become or make something lighter or brighter in color In the distance, the sky was beginning to brighten. brighten something a shampoo to brighten and condition your hair
- 2[intransitive, transitive] to become, feel, or look happier; to make someone look happier Her eyes brightened. brighten up He brightened up at their words of encouragement. brighten something (up) A smile brightened her face.
- 3[transitive, intransitive] brighten (something) (up) to become or make something become more pleasant or enjoyable; to bring hope A personal letter will usually brighten up a person's day.
- 4[transitive] brighten something (up) to make something look more brightly colored and attractive Fresh flowers will brighten up any room in the house.
- 5[intransitive] brighten (up) (of the weather) to improve and become brighter According to the forecast, it should brighten up later.
NAmE//ˈbraɪtn//Verb Forms present simple I / you / we / they brighten
he / she / it brightens
past simple brightened
-ing form brightening