Webster's Revised Unabridged Dictionary · 1913

Peanut gallery

Peanut gallery

1.
The cheapest seats in a theater, being typically those farthest from the stage, as in the uppermost balcony.
2.
In a television show for children, the section where visiting children sit as guests during the performance.
3.
Any group of children, or the children in a group of people; as, let's have no noise from the peanut gallery. [Colloquial]