Balloon is a flexible bag filled with gas, such as helium, hydrogen, nitrous oxide, oxygen, or air.
Modern balloons are made from materials such as rubber, latex, polychloroprene, or a nylon fabric.
The term "balloon" also refers to:
1. In medicine - a surgical tool used to widen narrow or blocked passages
2. In finance - a balloon payment, which is a large payment due at the end of a loan
3. In comics - a speech balloon containing characters' dialogue