The term 'Cartoon Sound' refers to the sound effects used in cartoons. The most common cartoon sound effects are 'Boing' (5 letters), 'Eek' (3 letters) and 'Pow' (3 letters). Boing is usually used to indicate a bouncing or springing action, while Eek is used to indicate surprise or fear. Pow is used to indicate a punch or explosion. All three of these sounds are commonly used in cartoons to add humor and excitement.