''Hecto'' (symbol: h) is a

decimal The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers of the Hindu–Arabic numeral ...

unit prefix A unit prefix is a specifier or mnemonic that is prepended to units of measurement to indicate multiples or fractions of the units. Units of various sizes are commonly formed by the use of such prefixes. The prefixes of the metric system, such as ...

in the

metric system The metric system is a system of measurement that succeeded the decimalised system based on the metre that had been introduced in France in the 1790s. The historical development of these systems culminated in the definition of the Interna ...

denoting a factor of one hundred. It was adopted as a multiplier in 1795, and comes from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

, meaning "hundred". In 19th century English it was sometimes spelled "hecato", in line with a puristic opinion by Thomas Young. Its unit symbol as an SI prefix in the International System of Units (SI) is the lower case letter h. The prefix is rarely used in general, but has certain specific applications: * hectopascal (hPa), in

meteorology Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not ...

, for

atmospheric pressure Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, ...

, the modern equivalent of the traditional

millibar The bar is a metric unit of pressure, but not part of the International System of Units (SI). It is defined as exactly equal to 100,000 Pa (100 kPa), or slightly less than the current average atmospheric pressure on Earth at sea leve ...

. *

hectolitre The litre (international spelling) or liter (American English spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metre (m3). ...

(hl or hL), in

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

, for liquids (notably

wine Wine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different varieties of grapes and strains of yeasts are m ...

and

milk Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. Immune factors and immune-modula ...

) and bulk commodities (e.g., grain). * hectogram (hg), in agronomy, for quantities of animal feed (hectogram/animal) and for measures of agricultural productivity (hectogram/hectare); also used in Italy abbreviated as , and in Canada, New Zealand and Sweden simply as 100 g, for retail sale of

cold cut Lunch meats—also known as cold cuts, luncheon meats, cooked meats, sliced meats, cold meats, sandwich meats, and deli meats—are precooked or cured meats that are sliced and served cold or hot. They are typically served in sandwiches or on ...

s and meat. *

hectometre The hectometre ( International spelling as used by the International Bureau of Weights and Measures; SI symbol: hm) or hectometer (American spelling) is a unit of length in the International System of Units (SI), equal to one hundred metres and t ...

(hm), in

radio astronomy Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation comin ...

, occasionally used to indicate a

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...

band Band or BAND may refer to: Places *Bánd, a village in Hungary *Band, Iran, a village in Urmia County, West Azerbaijan Province, Iran * Band, Mureș, a commune in Romania *Band-e Majid Khan, a village in Bukan County, West Azerbaijan Province, I ...

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, t ...

* In surveying, a square hectometre is called a

hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is a ...

(ha, or 100 '' ares'' = 1 hm² = 10,000 m²).

References

{{reflist SI prefixes 100 (number)

See also

References