As a noun, it is a colorless gas used in bright advertising signs and lighting. As an adjective, it describes very bright, glowing colors like those signs.
From Greek 'neos' meaning 'new', because it was a newly discovered element in 1898. Scientists chose the name to mark it as one of the 'new' gases.
Real neon gas actually glows a reddish-orange; other 'neon colors' in signs come from different gases and coatings. The element’s name literally means 'new', but now we use it to describe a very loud, retro kind of brightness.
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