/ˈbraɪtn ||; ˈbraɪtṇ/verb [I,T] brighten (sth) (up) to become brighter or happier; to make sth brighter 变得开心；开颜；（使）明亮: His face brightened when he saw her. 他一见到她便笑逐颜开。to brighten up sb's day (= make it happier) 给某人的生活增加姿彩