창문 is the overall conception of the window.In the ancient esten asia，there are many windows made by wood and papers.유리창，유리 means glass，창 is the main part of this word，it means window.so 유리창 means glass window.

창문: window, in general 유리창: glass window 창=window 문=door 유리=glass You can use the word 창문 for most cases. Use 유리창 if you need to be specific about window made of glass. eg) 창문을 닫아 주세요. 창문이 깨졌어요. 창문을 닦아 주세요.