What is the difference between a 'ton' a 'short ton' a 'long ton' a 'metric ton' and a 'ton'?

Ton/Short ton/Net ton: 2000 lbs (US and metric systems)

Long ton/Gross Ton: 2240 lbs (US and metric systems)

Tonne/Metric ton: 2250 lbs or 1000 kg (metric system only)

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The "Long Ton" (2240lbs) is called simply the "Ton" here in the UK, where in fact the tonne (1000kg) is now the official unit for trade and technical purposes.