the.com/aside
A whisper to the audience the other characters politely pretend not to hear.
means A remark spoken quietly, off to the side, meant for some ears but not all of them.
from From the phrase 'on side' — to set apart — formalized in theater where actors literally turned away to confide in the crowd.
Stage trickLets characters voice thoughts others can't hear
Hamlet's habitShakespeare weaponized asides for dramatic irony
Modern echoThe parenthetical (you know what I mean) is its descendant