틀이 · 틀을
frame; mold; framework
Example
생각의 틀을 깨면 새로운 아이디어가 나와요.
When you break out of your usual frame of thinking, new ideas come.
Word parts
Native word for any frame or mold, from window frames to frameworks of thought.
Good to know
틀에 박힌 means 'stereotyped, cookie-cutter', e.g. 틀에 박힌 생각 'clichéd thinking'.