A ton is a unit of measure that can refer to mass, volume, or force. As a unit of mass, it can mean:

• The long ton, which is 2,240 pounds (1,016.0 kilograms)
• The short ton, which is 2,000 pounds (907.2 kilograms)
• The tonne, also called the metric ton, which is 1,000 kilograms (about 2,204.6 pounds) or 1 megagram

The tonne is the most commonly used unit of measure for ton in most countries, while the short ton is used in the United States. The long ton is no longer officially used in the UK, which has moved to the metric system.

Its important to note that a ton and a tonne are not equal, and they have different weights. A ton is an imperial measurement, while a tonne is a metric measurement. A tonne is equal to 1,000 kilograms, while a short ton is equal to 907.2 kilograms and a long ton is equal to 1,016.0 kilograms.

In summary, a ton is a unit of measure that can refer to mass, volume, or force. As a unit of mass, it can refer to the long ton, short ton, or tonne, with the tonne being the most commonly used unit of measure for ton in most countries.