Balloon gas (6)

I believe the answer is:

helium

'balloon gas' is the definition.
(I've seen this in another clue)

This is all the clue.

(Other definitions for helium that I've seen before include "Balloon-filling element" , "Light colourless gas used in airships" , "Second lightest element" , "Lightest noble gas" , "Light colourless gas used in balloons" .)

I've seen this clue in the Evening Standard, The Daily Mail, the LA Times, The Mirror and the King Feature Syndicate.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.