The Greeks had a myth to explain the beginning of the universe.
They said it started with thin matter without structure that spread out everywhere.
They called this original matter “chaos.”
When the alchemist Jan van Helmont started noticing these airlike substances, he thought that chaos would be a good name for them.
However, Helmont spoke Flemish, so when he said “chaos” with a Flemish accent, it came out as “gas” and he spelled it as he pronounced it.