heliumnoun [ U ]uk /ˈhiː.li.əm/ us /ˈhiː.li.əm/ symbol He
Examples from literature
- But soon, balloonists started to use lighter-than-air gases like helium and hydrogen inside the balloon to fly higher.
- Hot air balloons are more common, but many of the high altitude balloons use helium gas.
- The gas used in the balloon is helium, which is not explosive like hydrogen, and therefore not as dangerous.