Gas in a glowing sign (4)

I believe the answer is:

neon

(Other definitions for neon that I've seen before include "One of the six inert gasses" , "Colourless gas, used in lighting" , "Atomic number 10" , "Colourless, odourless rare gas" , "Element 10, used in lights" .)

I've seen this clue in the Universal and the USA Today.

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.