• 開幕かいまく — opening of an event / performance
• 閉幕へいまく — closing of an event
• 幕府ばくふ — shogunate government
• 幕内まくうち — top division of sumo wrestlers
• 序幕じょまく — prologue / opening act
• 終幕しゅうまく — final act / conclusion

幕 is a phono-semantic compound: the radical 巾 (cloth) gives the meaning of a drape or curtain, while 莫 (バク) provides the sound. It originally described cloth curtains used on stage or in military tents, later extending to metaphorical uses like eras, acts, and scenes in history or drama.

試合しあいは 開幕かいまくしたばかりです。
The match has just started.

江戸えど幕府ばくふは 260年間ねんかんも 続つづいた。
The Edo Shogunate lasted for more than 260 years.