some discussion designed for the viewers and supposedly not heard because of the various other actors on stage.
A remark manufactured in an undertone in order to be inaudible to others close by.
A parenthetical departure; a digression.
An incidental comment made quietly to be able to be heard because of the person to whom it is said rather than by any others in area.
Something spoken aside; as, a remark produced by a stageplayer that your various other players aren't likely to hear.
Something spoken rather than heard, or supposed never to be heard, by some body or even more present; specifically, a remark uttered by an actor in the phase, and assumed to not ever be heard by the other characters regarding stage, or to be heard only by those for whom it is meant.
an email that departs from primary subject
a line talked by an actor into audience but not intended for other individuals on the phase