This is the 2020th most frequent Korean word.
불을
"불을" means "fire" or "light" in the accusative case in Korean.
In this sentence, '불을' refers to turning on a light or an appliance involving light or fire.
저녁 준비를 위해 불을 켰어요.
I turned on the light for dinner preparation.
Here, '불을' refers to creating a fire, specifically a campfire.
캠핑장에서 모닥불을 피웠어요.
We lit a campfire at the campsite.
In this case, '불을' refers to the warmth and light provided by a fire.