A tonne (t) or metric ton, also referred to as a metric tonne or tonne métrique, is a measurement of mass equal to 1,000 kilograms. It is not an SI unit but is accepted for use with the SI.  The proper SI unit for a tonne would be a "megagram" (Mg, see SI prefix), but this term is rarely used in practice. An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol to form a Decimal multiple or Though the spelling tonne predates the introduction of the SI system in 1960 (it has been used in France for centuries, where it comes from), it is now used as the standard spelling for the metric mass measurement in some English-speaking countries. In the United States the correct term is metric ton.  The comparable imperial and US customary units are spelled ton in English. Imperial units or the Imperial system is a collection of units first defined in the British Weights and Measures Act of 1824 US customary units, also known in the United States as English units or Imperial units (in reference to the British Empire) (but see English
In the USA this unit was defined in 1866 as a millier or a tonneau (both French words). The United States of America —commonly referred to as the This measure was used in Europe centuries earlier. However, neither of these latter words are in use in the USA and though they still appear in the statute, they have been declared obsolete by NIST. 
The femtotonne shares the same symbol (ft) as the foot. An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol to form a Decimal multiple or A foot (plural feet or foot; symbol or abbreviation ft or sometimes &prime – the prime symbol) is a non-SI unit The fractional multipliers are rarely used with the tonne unit basis, as the gram is both more fundamental and uses more familiar scaling factors. Hence 10 kilograms is more common than 10 millitonnes, or 5 ng rather than 5 ft.
The spelling tonne is from Gallic and French. French ( français,) is a Romance language spoken around the world by 118 million people as a native language and by about 180 to 260 million people The term applied to the barrel of the largest size. In Old English the spelling was tunne, "cask" - a full cask about a metre high could easily weigh a tonne. A barrel or cask is a hollow cylindrical container traditionally made of Wood Staves and bound with Iron Hoops The The antiquated British wine cask volume measurement tun is close to a metric tonne in weight as it defines about 954 litres which for most liquids amounts to as many kilograms.
One tonne is equivalent to:
The official symbol is t. T and mT and mt (especially in the combination mmt for "million metric tons" compare to Mt for megatonne) are also sometimes used, but all of these are deprecated since they conflict with internationally agreed SI symbols. T is the SI symbol for the tesla and m is SI prefix 'milli', meaning 1000th (though in practice fractional prefixes aren't generally used with the tonne). The tesla (symbol T) is the SI derived unit of Magnetic field B (which is also known as "magnetic flux density" and "magnetic Te is also sometimes used, particularly in the nuclear industry.
In France and the English-speaking countries that are predominantly metric, the spelling tonne is widespread. However, in Britain, the ton used prior to metrication was the long ton of 2240 pounds (approximately 1016 kg). This is so close to the tonne that many people draw little distinction and continue to use the old spelling. For example, even the Guinness Book of World Records accepts metrication without marking this by changing the spelling. Guinness World Records, known until 2000 as The Guinness Book of Records (and in previous U Metrication (or metrification refers to the introduction of the SI metric system as the International standard for physical measurements—a long-term series For the United States, metric ton is the name for this unit used and recommended by NIST, though it remains to be seen the impact of the "America COMPETES Act" of August 9, 2007 which amended the Metric Act of 1866's obsolete definition of the metric system and its tables of units and to explicitly express preference for SI instead. Events 48 BC - Caesar's civil war: Battle of Pharsalus - Julius Caesar decisively defeats Pompey at Pharsalus Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.  In the U. S. an unqualified mention of a "ton" almost invariably refers to a short ton of 2000 lb (about 907 kg). The short ton ( S/T) is a unit of mass equal to 2000 lb (around 907
Like grams and kilograms, tonnes gave rise to a (now obsolete) force unit of the same name: 1 tonne-force = 9. 80665 kilonewtons (kN), a unit also often called simply "tonne" or "metric ton" without identifying it as a unit of force. The newton (symbol N) is the SI derived unit of Force, named after Isaac Newton in recognition of his work on Classical Note that it is only the tonne as a unit of mass which is accepted for use with SI; the tonne-force or metric ton-force is not acceptable for use with SI.
The tonne of trinitrotoluene (TNT) is used as a proxy for energy. Trinitrotoluene ( TNT) is a Chemical compound with the formula C6H2(NO23CH3 Prefixes are also used e. g. kilotonne, megatonne, gigatonne; especially for expressing nuclear weapon yield, based on a specific combustion energy of TNT of 4. The explosive yield of a nuclear weapon is the amount of Energy, called the Yield, discharged when a Nuclear weapon is detonated expressed usually Energy density is the amount of Energy stored in a given system or region of space per unit Volume, or per unit Mass, depending on the context although 184 MJ/kg (or one calorie—specifically a thermochemical calorie—per milligram). The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity This article is about the unit of energy For its use in Nutrition and Food labelling regulations, see the article on Food energy. For other uses of the words gram or gramme see Gram (disambiguation. Hence, 1 kt TNT = 4. Units of mass There are three similar units of Mass called the ton: Long ton (simply ton in countries such as the United 184 TJ, 1 Mt TNT = 4. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity 184 PJ. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity
The SI unit of energy is the joule. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity Assuming that TNT contains 1000 small (thermochemical) calories per gram (4. This article is about the unit of energy For its use in Nutrition and Food labelling regulations, see the article on Food energy. 184 kJ/g), one tonne TNT is more correctly referred to as 4. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity 184 gigajoules. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity It is usually used to describe the energy of explosions.
metric ton unit
A metric ton unit (MTU) can mean 10 kg within metal (e. g. tungsten, manganese) trading, particularly within the USA. It traditionally referred to a metric ton of ore containing 1% (i. e. 10 kg) of metal.