noun
General term for lighter-than-air aircraft, including hot-air balloons, weather balloons, and blimps. Not used for toy balloons (風船).
気球に乗って空を飛んでみたい。
I want to ride in a balloon and fly through the sky.
気象観測用の気球が毎日打ち上げられている。
Weather balloons are launched every day.