noun
helium
The chemical element helium (He). Used in balloons, airships, and as a cooling agent.
ヘリウムガスを風船に入れると浮かぶ。
When you put helium gas into a balloon, it floats.
ヘリウムは無色無臭の気体だ。
Helium is a colorless, odorless gas.
From English 'helium', ultimately from Greek 'helios' (sun), as it was first detected in the solar spectrum.