It gives the audience insight to the motives of the character speaking, in a manner that suggests that while the audience is getting that information, the other characters onstage are not, thus allowing the audience to follow the plot without "giving anything away" to the other characters involved in the story.
An ASIDE.
They address an audience.
Aside
An 'aside'.
Aside
An ASIDE.
Aside
a remark made by an actor to the audience that other actors don't hear is called aside
Aside
They address an audience.
An 'aside'.
Aside
Narrator or aside
If an actor speaks directly to the audience it is called an aside. If an actor speaks to himself, while only the audience can hear, it is called soliloquy. The fourth wall is a hypothetical barrier between the actors and the audience. This barrier is broken when an actor interacts with the audience through an aside.
The aside is when a character on stage talks to the audience, but the other characters don't hear it.
In drama, the stage direction "aside" means lines are delivered to the audience, breaking the "fourth wall". http://en.wikipedia.org/wiki/Aside
Aside is when an actor speaks to the audience not the other members of a cast