A short ton is equal to 2,000 pounds and a long ton is 2,240 pounds. However, there are different types of tons, depending on the country.
In the United States, the ton most commonly used is the short ton. In the United Kingdom, a tonne is a metric ton and is equal to 1,000 kilograms or 2,240 pounds. To avoid confusion, these terms are commonly called "long tons" and short tons."
The term "ton" can also be used as a measurement of power. For example, in refrigeration, a ton is a unit of power. This is the unit of measurement required to freeze or melt a short ton of ice per day.
The word "ton" originates from the word "tub." At its inception, the word tub was used as a unit of measure for wine makers. Centuries ago, a wine maker's tub could fill 250 1-gallon wine bottles, each weighing 8 pounds, so the tub weighed 2,000 pounds.
Industries using the term "ton" include the aviation industry when measuring petroleum products. The shipping industry uses "deadweight tons" when measuring a ship's capacity, and "harbour ton," which is used in South Africa. A harbour ton is the same as a short ton, or 2,000 pounds.