You are wrong on that. It's the same thing just different places use different words. Just like "pencil lead" does not refer to lead. It refers to the thing in

You are wrong on that. It's the same thing just different places use different words. Just like "pencil lead" does not refer to lead. It refers to the thing inside a pencil. The composition of that changed over time but the name didn't. There are plenty other fix terms like "gas" (gasoline) or "tin foil hat" (a hat made out of aluminium foil) which everyone knows what is meant by it despite the word(s) describing something different. Nowhere in this thread anyone but you was taking about foils made out of tin metal.