Balloon n. : A bag made of silk or other light material, and filled with hydrogen gas or heated air, so as to rise and float in the atmosphere; especially, one with a car attached for aerial navigation.

Balloon n. : A ball or globe on the top of a pillar, church, etc., as at St. Paul's, in London.

Balloon n. : A round vessel, usually with a short neck, to hold or receive whatever is distilled; a glass vessel of a spherical form.

Balloon n. : A bomb or shell.

Balloon n. : A game played with a large inflated ball.

Balloon n. : The outline inclosing words represented as coming from the mouth of a pictured figure.

Balloon v. t. : To take up in, or as if in, a balloon.

Balloon v. i. : To go up or voyage in a balloon.

Balloon v. i. : To expand, or puff out, like a balloon.

Example:
What happened to a Balloon that is inflated with hydrogen gas, but in a few hours the baloon was deflated?

Taxonomy
balloons, helium, latex, rubber balloons, gas, Party balloons, helium balloons, free encyclopedia, hydrogen, drops, Water balloons, balloon sculptures, foil balloons, Rocket Balloon, 09-15, Flying machines, rubber balloon, mylar balloon.

Defination from the web:
balloon is an inflatable flexible bag filled with a type of gas, such as helium, hydrogen, nitrous oxide or air. ... The first balloon was invented by Brazilian-born Portuguese priest at 45 years of age, Bartolomeu de Gusmão, and the first public exhibition was ...