The story
Coined as part of Bill Cosby’s stand up act. It gained adoption when it was broadcast in an episode of The Cosby Show in 1986, where it was spelled ZRBTT.
Etymology from Wiktionary, CC BY-SA 4.0.
zerbert
Today it means: The sound made when someone places the mouth against skin and blows, imitative of the sound of flatulence. Full definition →