Category: Units of measurement

Barrer is a non-SI unit of gas permeability (specifically, gas permeability) used in the membrane technology and contact lens industry. It is named after Richard Barrer.
Erlang (unit)
The erlang (symbol E) is a dimensionless unit that is used in telephony as a measure of offered load or carried load on service-providing elements such as telephone circuits or telephone switching equ
Arbitrary unit
In science and technology, an arbitrary unit (abbreviated arb. unit, )or procedure defined unit (p.d.u.)is a relative unit of measurement to show the ratio of amount of substance, intensity, or other
Gross ton mile
Gross ton mile (GTM), or its related units gross tonne–kilometre and thousand gross tonne mile (kgtm) are units of measurement commonly used in rail transportation. Gross ton kilometre is the product
Percentage point
A percentage point or percent point is the unit for the arithmetic difference between two percentages. For example, moving up from 40 percent to 44 percent is an increase of 4 percentage points, but a
Hawking Index
The Hawking Index (HI) is a mock mathematical measure on how far people will, on average, read through a book before giving up. It was invented by American mathematician Jordan Ellenberg, who created
Cent (music)
The cent is a logarithmic unit of measure used for musical intervals. Twelve-tone equal temperament divides the octave into 12 semitones of 100 cents each. Typically, cents are used to express small i
International System of Electrical and Magnetic Units
The International System of Electrical and Magnetic Units is an obsolete system of units used for measuring electrical and magnetic quantities. It was proposed as a system of practical international u
Unit of measurement
A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of
Degrees of general hardness (dGH or °GH) is a unit of water hardness, specifically of general hardness. General hardness is a measure of the concentration of divalent metal ions such as calcium (Ca2+)
Acoustic ohm
The acoustic ohm is a unit of measurement of acoustic impedance, which is the ratio of acoustic pressure to acoustic volume flow. In SI units, pressure is measured in pascals and flow in m3/s, so the
Peg (unit)
A peg is a unit of volume, typically used to measure amounts of liquor in the Indian subcontinent. Informally, a peg is an undefined measure of any alcoholic drink poured in a glass. The terms "large
Wool bale
A wool bale is a standard sized and weighted pack of classed wool compressed by the mechanical means of a wool press. This is the regulation required method of packaging for wool, to keep it uncontami
Per cent mille
A per cent mille or pcm is one one-thousandth of a percent. It can be thought of as a "milli-percent". It is commonly used in epidemiology, and in nuclear reactor engineering as a unit of reactivity.
Hank (unit of measure)
In the textile industry, a hank is a coiled or wrapped unit of yarn or twine, as opposed to other materials like thread or rope, as well as other forms such as ball, cone, bobbin (cylinder-like struct
Windisch–Kolbach unit
°WK or degrees Windisch-Kolbach is a unit for measuring the diastatic power of malt, named after the German brewer and the Luxembourg brewer . It is a common unit in beer brewing (especially in Europe
Conversion of units
Conversion of units is the conversion between different units of measurement for the same quantity, typically through multiplicative conversion factors which change the measured quantity value without
Thermal dose unit
A Thermal dose unit (TDU) is a unit of measurement used in the oil and gas industry to measure exposure to thermal radiation. It is a function of intensity (power per unit area) and exposure time. 1 T
In genetics, a centimorgan (abbreviated cM) or map unit (m.u.) is a unit for measuring genetic linkage. It is defined as the distance between chromosome positions (also termed loci or markers) for whi
Toxic unit
Toxic units (TU) are used in the field of toxicology to quantify the interactions of toxicants in binary mixtures of chemicals. A toxic unit for a given compound is based on the concentration at which
The jansky (symbol Jy, plural janskys) is a non-SI unit of spectral flux density, or spectral irradiance, used especially in radio astronomy. It is equivalent to 10−26 watts per square metre per hertz
Sharp Scale
The Sharp Scale was devised by Henrietta Sharp Cockrell as an objective and scientific way to measure the opacity of paper, particularly of manuscript folios, 'in the field' without specialized equipm
Comparative Tracking Index
The Comparative Tracking Index (CTI) is used to measure the electrical breakdown (tracking) properties of an insulating material. Tracking is an electrical breakdown on the surface of an insulating ma
In telecommunication, a call-second is a unit used to measure communications traffic density, equivalent to one call with a duration of one second. Traffic is measured independent of users. For exampl
Helen (unit)
A helen is a humorous unit of measurement based on the concept that Helen of Troy, from the Iliad, had a "face that launched a thousand ships". The helen is thus used to measure quantities of beauty i
Units of textile measurement
Textile fibers, threads, yarns and fabrics are measured in a multiplicity of units. * A fiber, a single filament of natural material, such as cotton, linen or wool, or artificial material such as nyl
The ampere-turn (A⋅t) is the MKS (metre–kilogram–second) unit of magnetomotive force (MMF), represented by a direct current of one ampere flowing in a single-turn loop in a vacuum. "Turns" refers to t
Indian units of measurement
Before the introduction of the Metric system, one may divide the history of Indian systems of measurement into three main periods: the pre-Akbar's period, the period of the Akbar system, and the Briti
Langley (unit)
The langley (Ly) is a unit of heat transmission, especially used to express the rate of solar radiation (or insolation) received by the earth. The unit was proposed by in 1942 and named after Samuel L
Darcy (unit)
The darcy (or darcy unit) and millidarcy (md or mD) are units of permeability, named after Henry Darcy. They are not SI units, but they are widely used in petroleum engineering and geology. The unit h
dBc (decibels relative to the carrier) is the power ratio of a signal to a carrier signal, expressed in decibels. For example, phase noise is expressed in dBc/Hz at a given frequency offset from the c
Potrzebie (/pɒtrəˈziːbi/; Polish pronunciation: [pɔtˈʂɛbʲe] dative/locative of potrzeba, "a need") is a Polish word popularized by its non sequitur use as a running gag in the early issues of Mad not
IEEE Std 260.1-2004
IEEE Std 260.1-2004 was a standard from the Institute of Electrical and Electronics Engineers that provided standard letter symbols for units of measurement for use in all applications in multiple con
Logarithmic units
No description available.
Snowden (physics)
A Snowden is a unit of soft X-ray emissivity, equivalent to ROSAT counts . These units were chosen by S. L. Snowden when working with the ROSAT mission to create the ROSAT All-Sky Survey in order to m
InHour is a unit of reactivity of a nuclear reactor. It stands for the inverse of an hour. It is equal to the inverse of the period in hours. One InHour is the amount of reactivity needed to increase
A ratl (رطل ) is a medieval Middle Eastern unit of measurement found in several historic recipes. The term was used to measure both liquid and weight (around a pound and a pint in 10th century Baghdad
Olf (unit)
The olf is a unit used to measure the strength of a pollution source. It was introduced by Danish professor P. Ole Fanger; the name "olf" is derived from the Latin word olfactus, meaning "smelled". On
Cape foot
A Cape foot is a unit of length defined as 1.0330 English feet (and equal to 12.396 English inches, or 0.31485557516 meters) found in documents of belts and diagrams relating to landed property. It wa
A dioptre (British spelling) or diopter (American spelling) is a unit of measurement with dimension of reciprocal length, equivalent to one reciprocal metre, 1 dioptre = 1 m−1. It is normally used to
Unit of alcohol
Units of alcohol are used in the United Kingdom (UK) as a measure to quantify the actual alcoholic content within a given volume of an alcoholic beverage, in order to provide guidance on total alcohol
A vitasti (Sanskrit: वितस्ति, vitasti) is an ancient Indian unit of length approximating to 21 centimeters.
pCO2, pCO2, or is the partial pressure of carbon dioxide (CO2), often used in reference to blood but also used in meteorology, climate science, oceanography, and limnology to describe the fractional p
Sabin (unit)
The sabin (or more precisely the square foot sabin) is a unit of sound absorption, used for expressing the total effective absorption for the interior of a room. Sound absorption can be expressed in t
International unit
In pharmacology, the international unit (IU) is a unit of measurement for the effect, not mass of a substance; the variance is based on the biological activity or effect, for the purpose of easier com
The savart /səˈvɑːr/ is a unit of measurement for musical pitch intervals. One savart is equal to one thousandth of a decade (10/1: 3,986.313714 cents): 3.9863 cents. Musically, in just intonation, th
The neper (symbol: Np) is a logarithmic unit for ratios of measurements of physical field and power quantities, such as gain and loss of electronic signals. The unit's name is derived from the name of
Dobson unit
The Dobson unit (DU) is a unit of measurement of the amount of a trace gas in a vertical column through the Earth's atmosphere. It originated, and continues to be primarily used in respect to, atmosph
The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals w
The millioctave (moct) is a unit of measurement for musical intervals. As is expected from the prefix milli-, a millioctave is defined as 1/1000 of an octave. From this it follows that one millioctave
Dollar (reactivity)
A dollar is a unit of reactivity for a nuclear reactor, calibrated to the interval between the conditions of delayed criticality and prompt criticality. Zero dollars is defined to be the threshold of
The penrig is a unit of tumescence, specifically for the tumescence of the human penis. It is defined as the tumescence that will raise 100 grams of penile tissue through one millimetre. The word is f
The newton-second (also newton second; symbol: N⋅s or N s) is the unit of impulse in the International System of Units (SI). It is dimensionally equivalent to the momentum unit kilogram-metre per seco
Welsh units
Welsh units of measurement are those in use in Wales between the Sub-Roman period (prior to which the Britons used Roman units) and the 13th-century Edwardian conquest (after which English units were
Grain per gallon
The grain per gallon (gpg) is a unit of water hardness defined as 1 grain (64.8 milligrams) of calcium carbonate dissolved in 1 US gallon of water (3.785412 L). It translates into 1 part in about 58,0
Dhanusha (unit)
Dhanusha is an ancient unit of measuring height used in Jain literature.
Gilbert (unit)
The gilbert (symbol: Gb) is an obsolete unit used in practical cgs and CGS-EMU systems to measure magnetomotive force. The unit is named for English physicist William Gilbert. Definition: * 1 Gb = (1
Column inch
A column inch was the standard measurement of the amount of content in published works that use multiple columns per page. A column inch is a unit of space one column wide by 1 inch (25 mm) high.
Thomson (unit)
The thomson (symbol: Th) is a unit that has appeared infrequently in scientific literature relating to the field of mass spectrometry as a unit of mass-to-charge ratio. The unit was proposed by Cooks
Log reduction
Log reduction is a measure of how thoroughly a decontamination process reduces the concentration of a contaminant. It is defined as the common logarithm of the ratio of the levels of contamination bef
IRE (unit)
The IRE unit is used in the measurement of composite video signals. Its name is derived from the initials of the Institute of Radio Engineers. A value of 100 IRE is defined to be +714 mV in an analog
Buckingham (unit)
The buckingham (symbol: B) is a CGS unit of electric quadrupole, named in honour of the chemical physicist A. David Buckingham who was the first to measure a molecular quadrupole moment. It is defined
Gurley unit
No description available.
Tog (unit)
The tog is a measure of thermal insulance of a unit area, also known as thermal resistance. It is commonly used in the textile industry and often seen quoted on, for example, duvets and carpet underla
Kauri-butanol value
The Kauri-butanol value ("Kb value") is an international, standardized measure of solvent power for a hydrocarbon solvent, and is governed by an ASTM standardized test, ASTM D1133. The result of this
Entropy unit
The entropy unit is a non-S.I. unit of thermodynamic entropy, usually denoted "e.u." and equal to one calorie per kelvin per mole, or 4.184 joules per kelvin per mole. Entropy units are primarily used
A Rayl, rayl or Rayleigh is one of two units of specific acoustic impedance or, equivalently, characteristic acoustic impedance; one an MKS unit, and the other a CGS unit. These have the same dimensio
The decipol is a unit used to measure the perceived air quality. It was introduced by Danish professor P. Ole Fanger. One decipol (dp) is the (PAQ) in a space with a of one olf (one standard person) v
Montevideo units
Montevideo units are a method of measuring uterine performance during labor. They were created in 1949 by two physicians, Roberto Caldeyro-Barcia and , from Montevideo, Uruguay. They are exactly equal
Contracted from the term micro reciprocal degree, the mired is a unit of measurement used to express color temperature. Values in mireds are calculated by the formula: where T is the colour temperatur
Rod (unit)
The rod, perch, or pole (sometimes also lug) is a surveyor's tool and unit of length of various historical definitions, often between approximately 3 and 8 meters (9 ft 10 in and 26 ft 2 in). In moder
Flick (physics)
In optical engineering and telecommunications engineering, the flick is a unit of spectral radiance. One flick corresponds to a spectral radiance of 1 watt per steradian per square centimeter of surfa
The symbol dBrn or dB(rn) is an abbreviation for decibels above reference noise. Weighted noise power in dB is referred to 1.0 picowatt. Thus, 0 dBrn = -90 dBm. Use of 144 line, 144-receiver, or C-mes
The term "cuerda" (Spanish for rope) refers to a unit of measurement in some Spanish-speaking regions, including Puerto Rico, Guatemala, Cuba, Spain, and Paraguay. In Puerto Rico, the term cuerda (and
Circular measure
A circular measure was used in comparing circular cross-sections, e.g., of wires, etc. A circular unit of the ares is the area of the circle whose diameter is one linear unit. For example, 1 circular
Automatic baud rate detection
Automatic baud rate detection (ABR, autobaud) refers to the process by which a receiving device (such as a modem) determines the speed, code level, start bit, and stop bits of incoming data by examini
Eotvos (unit)
The eotvos is a unit of acceleration divided by distance that was used in conjunction with the older centimetre–gram–second system of units (cgs). The eotvos is defined as 10−9 galileos per centimetre
Saybolt universal viscosity
Saybolt universal viscosity (SUV), and the related Saybolt FUROL viscosity (SFV), are specific standardised tests producing measures of kinematic viscosity. FUROL is an acronym for fuel and road oil.
Scoville scale
The Scoville scale is a measurement of the pungency (spiciness or "heat") of chili peppers, as recorded in Scoville heat units (SHU), based on the concentration of capsaicinoids, among which capsaicin
Measurement of land in Punjab
The following are the basic measurements of land used in the Punjab region, divided between Indian and Pakistani Punjab and many parts of North India and Pakistan in ascending order.
GNU Units
GNU Units is a cross-platform computer program for conversion of units of quantities. It has a database of measurement units, including esoteric and historical units. This for instance allows conversi
Parts-per notation
In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractio
The caballería (lit. 'cavalry') was a unit of land measurement in the Spanish viceroyalties in the Americas during the times of the Spanish Empire in the 16th through 19th centuries Spanish West Indie
In chemistry, pH (/piːˈeɪtʃ/), historically denoting "potential of hydrogen" (or "power of hydrogen"), is a scale used to specify the acidity or basicity of an aqueous solution. Acidic solutions (solu
Perm (unit)
A perm is a unit of permeance or "water vapor transmission" given a certain differential in partial pressures on either side of a material or membrane.
A micromort (from micro- and mortality) is a unit of risk defined as a one-in-a-million chance of death. Micromorts can be used to measure the riskiness of various day-to-day activities. A microprobab
International yard and pound
The international yard and pound are two units of measurement that were the subject of an agreement among representatives of six nations signed on 1 July 1959; the United States, United Kingdom, Canad
Medieval weights and measures
The following systems arose from earlier systems, and in many cases utilise parts of much older systems. For the most part they were used to varying degrees in the Middle Ages and surrounding time per