There are 3 different types of model engines generally used and each has got their own commonly used name so we know what they are and what fuel they use.

The first type is spark ignition which uses gasoline (called petrol outside of America) and of course that gets shortened to just "gas". Outside of America gas is only used when referring to LPG (Liquified Petroleum Gas for cars) and house heating.

The second type is glow ignition which uses methanol as the basic fuel but because they use a glow plug to ignite the methanol then they're commonly called glow engines. Outside of America no glow engine is called a "gas" engine.

To confuse things even more, you're likely to hear of "nitro" engines. This is very common with the glow engines used in RC cars because they like to use lots of nitro in the basic fuel which is still just methanol. But nitro sounds powerful and it didn't take long for the advertisers to catch on that kids love the idea of power so even the big glossy ads in magazines talk about "nitro" engines and then they sell lots of expensive high nitro fuels to them . Just remember that a "nitro" engine is only a glow engine.

The third type is what we call a diesel but isn't strictly a true diesel, it's just easier to say than "compression ignition" . These use a fuel made with oil/kerosene/ether and don't use any source of ignition other than heating up the air by compressing it very quickly.