That's a separate, third kind of ton (hurray standards!). The tonne is a metric measurement for 1000kg. American and UK tons are different amounts, but spelled

That's a separate, third kind of ton (hurray standards!). The tonne is a metric measurement for 1000kg. American and UK tons are different amounts, but spelled the same way. They're known as short ton and long ton respectively. America also uses the long ton and the metric tonne for some applications without differentiating the names at all.