This is the 3208th most frequent Korean word.
공기
"공기" means "air."
In this case, '공기' again refers to 'air,' emphasizing its state within a confined space like a room.
방 안의 공기를 환기하려고 창문을 열었어요.
To ventilate the room's air, I opened the window.
In this sentence, '공기' means 'air' as the invisible mixture of gases that surrounds the Earth and is necessary for breathing.
맑은 공기가 건강에 좋습니다.
Fresh air is good for health.
Here, '공기' refers to 'air' as a physical entity that can be infused into or mixed with something to affect texture or experience.