幕

Traditionally explained as an ideogrammic compound:

莫 (없을 막) – represents the idea of covering or obscuring (like the darkness of evening);

巾 (건, “cloth”) – indicates cloth, drapery

Together, they depict a large piece of cloth used to cover or hang down, i.e., a curtain or tent flap.

It is widely used for stage curtains, ceremonial tents, and metaphorical “curtains” like the opening (開幕) or closing (閉幕) of events.