If you are onstage, you are on the stage in a theatre, in front of the audience, during a show. Actors go onstage when it is their turn; they leave and are then offstage.

If you are onstage如果你 onstage（在舞台上），you are on the stage in a theatre表示你在劇場的舞台上，in front of the audience在觀眾面前，during a show演出正在進行。Actors go onstage when it is their turn演員輪到自己的時候就 onstage 上台；they leave and are then offstage下場之後就是 offstage（在幕後）。

People also use it more loosely for any public performance space — a concert, a school play, a talk with a microphone. It works as an adjective (an onstage fight, meaning the fight is part of the play) and as an adverb (she appeared onstage).

People also use it more loosely for any public performance space人們也會用得比較寬鬆，指任何公開表演的場合——a concert, a school play, a talk with a microphone演唱會、學校的戲劇公演、拿麥克風的演講。It它 works as an adjective可以當形容詞 (an onstage fight, meaning the fight is part of the play)（an onstage fight，指這場打鬥是戲的一部分） and as an adverb也可以當副詞 (she appeared onstage)（she appeared onstage，她出現在台上）。

You will also see on-stage and on stage. All three exist; the one-word form is common in theatre writing. It is a practical word, not a fancy one.

You will also see on-stage and on stage你也會看到 on-stage 和 on stage 這兩種寫法。All three exist三種寫法都存在；the one-word form is common in theatre writing連寫成一個字的形式在戲劇文章裡比較常見。It這 is a practical word是個實用的字，not a fancy one不是個花俏的字。

Though actually, on stage as two words often just tells you where someone is right now, while onstage as one word more often names the performing space as a kind of world: onstage manners, onstage chemistry.

Though actually但其實，on stage as two words often just tells you where someone is right now寫成兩個字的 on stage 常常只是告訴你某人現在人在哪裡，while onstage as one word more often names the performing space as a kind of world而寫成一個字的 onstage 比較常用來把表演空間當成一種世界來講：onstage manners, onstage chemistryonstage manners（台上的舉止）、onstage chemistry（台上的默契）。