• 灯台とうだい — lighthouse
• 灯油とうゆ — kerosene
• 点灯てんとう — lighting / turning on a light
• 消灯しょうとう — lights out
• 街灯がいとう — street lamp
• 提灯ちょうちん — paper lantern

The radical 火 (fire) plus 丁 (phonetic element) formed the character 灯, symbolizing a small controlled flame. It evolved to mean “lamp” or “light source” and is often used in compounds describing artificial illumination, such as lighthouses or street lamps.

街灯がいとうが 道みちを照てらしている。
The streetlights are illuminating the road.

灯台とうだいは 夜よるの海うみを照てらす。
The lighthouse lights up the sea at night.

部屋へやの灯ひを消けして寝ねました。
I turned off the light and went to sleep.