1. curtain
いよいよ幕を開けようとしていた。The curtain was finally about to open.
2. act (in a play)
さあ、第二幕が始まります。Now, the second act begins.
3. falling of the curtain; end (of a scene)
これにて今夜の舞台は幕となります。This concludes tonight's performance.
4. end; close
悪いが、ここで幕だ。Sorry, but this is where it ends.
5. case; occasion; role (to play); part; place
だんだん僕の出る幕がなくなってきたね。There's less and less for me to do, isn't there?
6. makuuchi; top division