Gas is short for gasoline, which is what we're putting in our cars. Petrol is short for petroleum, which is not what Europeans are putting in their cars. Remind me again which colloquial wording makes the most sense?
Well I dunno, last time I checked by far most of Europe does in fact not call it petrol. I can't claim to know which word is most commonly used, but as an anecdote the dutch call it "benzine" which is also "wrong" but in a different way from both gas and petrol.
Seems to me no one can figure out what the proper name for this stuff ought to be :P
gasoline -> gas at least has a certain logic to it, even though "gas" is unfortunately already a word that means something rather opposite. "Petrol" has always seemed strange to me, too, though, since nobody pumps black sludge ("petroleum") into their car but rather the clear, fluid petroleum distillate called gasoline.
I got curious, and "Gasoline" apparently comes from "Gazoline", which Samuel Boyd used to avoid trademark infringement with Patent Cazeline Oil (for use in artificial light), which was named after John Cassell. [1]