We installed several nightlights in our child's room so he wouldn't be scared at night.

nightlights 是复合名词，由 night（夜晚）和 lights（灯）组成，指"夜间使用的低亮度照明灯"，即"小夜灯"。这种灯通常光线柔和，用于夜间提供微弱照明而不影响睡眠。