"Doh" is an exclamation often used to express frustration, disappointment, or realization of a mistake. It gained popularity through the character Homer Simpson from the animated television show The Simpsons. When Homer utters "Doh," it typically follows a blunder or a moment of foolishness, making it a relatable expression for many. The term has transcended its original context and is now widely recognized in popular culture. It is often used humorously in everyday situations when someone realizes they have made an error or overlooked something obvious. This simple sound captures a universal feeling of exasperation.