Definition for the word aside in english

T or toward the side. step aside.

I suspect that you teacher wants to know what an "aside" is in a play. In plays, an aside happens when a character says something aloud on stage, but the audience understands that the other characters on the stage cannot hear what the speaker is saying. In other words, the actor turns aside form the other characters, appearing to speak to himself or herself alone. This is a way of giving the audience information about what the character is thinking without having the other characters appear to know the same information.