This is the 311th most frequent Korean word.
날
"날" means "day" in English.
날 is used to refer to a 'day' or a specific day here.
날씨가 좋은 날에는 산책을 가는 것을 좋아해요.
I like to go for a walk on days when the weather is nice.
날 is used as the stem of the verb 'to fly' (날다) here.
새가 하늘을 날고 있어요.
The bird is flying in the sky.
날 is not present directly here, but if referring to the action affecting 'me' or a 'sharp' incident, it could relate metaphorically.