This is the 1918th most frequent Korean word.
낼
"낼" means "tomorrow" in Korean.
Here, '낸' ('내일') denotes 'tomorrow', referring to the next day.
나는 내일 학교에 갈 거야.
I will go to school tomorrow.
Here, '낼' is part of '내질렀다', which means 'shouted'; it modifies the act of exerting a loud sound.
그는 화를 참지 못하고 소리를 내질렀다.
He couldn't hold his anger and shouted.
Here, '내기' ('bet') is a noun derived from the verb '내다', meaning 'to make or put forth'.