lighten

/ˈlaɪ.t̬ən/

动词

变浅，变淡
The sky began to lighten as the sun rose above the horizon.
天空开始变亮，太阳从地平线升起。
使变淡，使变浅
（使）心情好转，（使）高兴起来
He tried to lighten the atmosphere by telling a joke.
他想通过讲笑话来缓解一下气氛。