Stage whisper? (5,1,3)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">stage whisper</span>' is the definition.<br/ ><span class="explanation-format__explanation">(both can mean a remark heard by an audience)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for aside that I've seen before include "Where one's taken for intimacy" , "Remark by an actor, directly to audience say" , "private" , "(Pushed) out of the way" , "Aides (anag.)" .)
(Other definitions for break a leg that I've seen before include "leading to member being in cast?" , "but not on the piste" , "Do something that requires surgery" , "Good luck in the theatre!" , "Actors' good luck" .)