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Freebase Staff for the Measurement Unit Commons
Topic is one of the core types in Freebase. Topics contain a set of default properties that are generally useful when describing a topic: display name, alias, article, image and webpage.
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| x name | x image | x Also known as | x article | x Subjects |
| Albedo |
The albedo of an object is the extent to which it diffusely reflects light from light sources such as the Sun. It is therefore a more specific form of the term reflectivity. Albedo is defined as the ratio of diffusely reflected to incident...
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| Atomic number |
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proton number |
In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The...
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| Ampere |
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Amp |
The ampere (symbol: A) is the SI unit of electric current. The ampere, in practice often shortened to amp, is an SI base unit, and is named after André-Marie Ampère, one of the main discoverers of electromagnetism.
In practical terms, the ampere is...
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| Amperes | ||||
| Angle |
In geometry and trigonometry, an angle (in full, plane angle) is the figure formed by two rays sharing a common endpoint, called the vertex of the angle (Sidorov 2001). The magnitude of the angle is the "amount of rotation" that separates the two...
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| Area |
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Area is a quantity expressing the two-dimensional size of a defined part of a surface, typically a region bounded by a closed curve. The term surface area refers to the total area of the exposed surface of a 3-dimensional solid, such as the sum of...
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| Astronomical unit |
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A.U. |
An astronomical unit (abbreviated as AU, au, a.u., or sometimes ua) is a unit of length equal to approximately 150 million kilometres (93 million miles). It is defined by the International Astronomical Union, and is defined as the mean distance...
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| Astronomical Units | ||||
| Acre | International acre |
The acre is a unit of area in a number of different systems, including the imperial and U.S. customary systems. The most commonly used acres today are the international acre and, in the United States, the survey acre.
One international acre is equal...
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| Acres | ||||
| Unit of alcohol |
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In the United Kingdom, a unit of alcohol is defined as 10 millilitres (or approximately 8 grams) of ethanol (ethyl alcohol). This is approximately the amount of ethanol an average healthy adult can break down in an hour. It is used as a basis for...
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| Minute of arc | Arcminute |
A minute of arc or arcminute (MOA) is a unit of angular measurement, equal to one sixtieth (1/60) of one degree. Since one degree is defined as one three hundred sixtieth (1/360) of a circle, 1 minute of arc is 1/21,600 of the amount of arc in a...
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| Arcminutes | ||||
| Minutes of arc | ||||
| Acceleration |
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In physics, and more specifically kinematics, acceleration is the change in velocity over time. Because velocity is a vector, it can change in two ways: a change in magnitude and/or a change in direction. In one dimension, i.e. a line, acceleration...
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| Angular momentum |
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Angular momentum is a vector quantity that is useful in describing the rotational state of a physical system. The angular momentum L of a particle with respect to some point of origin is a
where r is the particle's position from the origin, p = mv...
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| Ammeter |
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An ammeter is a measuring instrument used to measure the electric current in a circuit. Electric currents are measured in amperes (A), hence the name. Smaller values of current can be measured using a milliameter or a microammeter. Early ammeters...
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| Anemometer |
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An anemometer is a device for measuring the wind speed, and is one instrument used in a weather station. The term is derived from the Greek word anemos, meaning wind. The first known description of an anemometer was given by Leon Battista Alberti in...
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| Bit |
A bit is the basic unit of information in computing and telecommunications; it is the maximum amount of information that can be stored by a device or other physical system that can normally exist in only two distinct states. These may be the two...
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| Byte | octet |
The byte (pronounced /ˈbaɪt/) is a unit of digital information in computing and telecommunications. It is an ordered collection of bits, in which each bit denotes the binary value of 1 or 0. Historically, a byte was the number of bits (typically 6,7...
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| Bytes | ||||
| British thermal unit | BTU |
The British thermal unit (BTU or Btu) is a traditional unit of energy equal to about 1.06 kilojoules. It is approximately the amount of energy needed to heat one pound of water one degree Fahrenheit. It is used in the power, steam generation,...
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| British thermal units | ||||
| Candela |
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Candelas |
The candela (pronounced /kænˈdɛlə/ or /kænˈdiːlə/, symbol: cd) is the SI base unit of luminous intensity; that is, power emitted by a light source in a particular direction, weighted by the luminosity function (a standardized model of the...
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| Year | Calendar year |
Generally speaking, a calendar year begins on the New Year's Day of the given calendar system and ends on the day before the following New Year's Day. By convention, a calendar year consists of a natural number of days. To reconcile the calendar...
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| Catalysis |
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Catalysis is the process in which the rate of a chemical reaction is either increased or decreased by means of a chemical substance known as a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by...
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| Electric current |
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Electric current can mean, depending on the context, a flow of electric charge (a phenomenon) or the rate of flow of electric charge (a quantity). This flowing electric charge is typically carried by moving electrons, in a conductor such as wire; in...
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| Calorie |
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Thermochemical calorie |
The calorie is a pre-SI metric unit of energy. The unit was first defined by Professor Nicolas Clément in 1824 as a unit of heat. This definition entered French and English dictionaries between 1841 and 1867. In most fields its use is archaic,...
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| Calories | ||||
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| Clock |
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A clock is an instrument used to indicate, measure, keep, and co-ordinate time. The word clock is derived ultimately (via Dutch, Northern French, and Medieval Latin) from the Celtic words clagan and clocca meaning "bell". For horologists and other...
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| Degree Celsius |
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Celsius |
Celsius (also historically known as centigrade) is a temperature scale that is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale two years before his death. The degree Celsius (°C) can refer to...
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| Degrees Celsius | ||||
| °C | ||||
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| Centimeter |
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cm |
A centimetre (American spelling: centimeter, symbol cm) is a unit of length in the metric system, equal to one hundredth of a metre, which is the current SI base unit of length. Centi is the SI prefix for a factor of 10. Hence a centimetre can be...
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| Centimetre | ||||
| Centimeters | ||||
| Centimetres | ||||
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| Day |
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Days |
A day (symbol d) is a unit of time equivalent to approximately 24 hours. It is not an SI unit but it is accepted for use with SI. The SI unit of time is the second.
The word 'day' can also refer to the (roughly) half of the day that is not night,...
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| Density |
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The density of a material is defined as its mass per unit volume. The symbol of density is ρ (the Greek letter rho).
Mathematically:
where:
Different materials usually have different densities, so density is an important concept regarding buoyancy,...
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| Dyne | Dynes |
In physics, the dyne (symbol "dyn", from Greek δύναμις (dynamis) meaning power, force) is a unit of force specified in the centimetre-gram-second (CGS) system of units, a predecessor of the modern SI. One dyne is equal to exactly 10 µN. Equivalently...
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| Electronvolt |
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eV |
In physics, the electron volt (symbol eV; also written electronvolt according to the NIST, IUPAC, and BIPM) is a unit of energy. By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates...
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| Electronvolts | ||||
| Electron volt | ||||
| Electron volts | ||||
| Energy |
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In physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working") is a scalar physical quantity that describes the amount of work that can be performed by a force, an attribute of objects and...
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| Exabyte |
An exabyte (derived from the SI prefix exa-) is a unit of information or computer storage equal to one quintillion bytes (short scale). It is commonly abbreviated EB. When used with byte multiples, the unit indicates a power of 1000:
The term...
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| Electric charge |
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Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields. The interaction between a moving...
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| Erg |
An erg is the unit of energy and mechanical work in the centimetre-gram-second (CGS) system of units, symbol "erg". Its name is derived from the Greek ergon, meaning "work".
An erg is the amount of work done by a force of one dyne exerted for a...
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| Frequency |
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency. The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency.
For cyclical...
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| Force |
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The Force is a binding, metaphysical and ubiquitous power in, it is the object of the Jedi and Sith monastic orders.
George Lucas, the creator of the Star Wars films, has attributed the origins of "The Force" to the 1963 Arthur Lipsett abstract film...
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| Floating point |
In computing, floating point describes a system for representing numbers that would be too large or too small to be represented as integers. Numbers are in general represented approximately to a fixed number of significant digits and scaled using an...
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| Furlong |
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Furlongs |
A furlong is a measure of distance in imperial units and U.S. customary units. It is equal to one-eighth of a mile, 220 yards, 660 feet, 201.168 meters, or 10 chains.
Five furlongs are approximately 1 kilometer (1.00584 km to be exact). Since the...
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| Degree Fahrenheit |
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Fahrenheit |
Fahrenheit is the temperature scale proposed in 1724 by, and named after, the physicist Daniel Gabriel Fahrenheit (1686–1736). Today, the temperature scale has been replaced by the Celsius scale in most countries. It is still in use for non...
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| Degrees Fahrenheit | ||||
| °F | ||||
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| Geographical mile |
The geographical mile is a unit of length determined by 1 minute of arc along the Earth's equator. For the 1924 International Spheriod this equalled 1855.4 metres. Any greater precision depends more on choice of standard than on more careful...
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| Gigabyte | GByte |
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 10 in the International System of Units (SI), therefore 1 gigabyte is 1000000000bytes. The unit symbol for the gigabyte is GB or Gbyte, but not Gb ...
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| Gigabytes | ||||
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| Gallon (US) |
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US liquid gallon |
A gallon is a measure of volume of approximately four litres. Historically it has had many different definitions, but there are three definitions in current use. These are the U.S. liquid gallon (≈ 3.8 L) and the lesser used U.S. dry gallon (≈ 4.4 L...
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| US gallon | ||||
| Gallon | ||||
| Gallons | ||||
| U.S. gallon | ||||
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| Hogshead |
A hogshead is a large cask of liquid (or, less often, of a food commodity). More specifically, it refers to a specified volume, measured in either Imperial units or U.S. customary units, primarily applied to alcoholic beverages such as wine, ale, or...
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| Hour |
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Hrs |
The hour (common symbol h or hr) is a unit of time. It is not an SI unit but is accepted for use with the SI.
In modern usage, an hour is a unit of measurement of time of the duration of 60 minutes, or 3600 seconds. It is 1/24 of a median Earth day....
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| Horsepower | Hp |
Horsepower (hp, HP or Hp) is the name of several non-SI units of power, with the most common units equal to between 735.5 (metric horsepower) and 746 watts.
The term "horsepower" was originally defined to allow the output of steam engines to be...
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| Hertz | 1/s |
The hertz (symbol: Hz) is a unit of frequency. It is defined as the number of complete cycles per second. It is the basic unit of frequency in the International System of Units (SI), and is used worldwide in both general-purpose and scientific...
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| Integer |
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The integers (from the Latin integer, literally "untouched", hence "whole": the word entire comes from the same origin, but via French) are formed by the natural numbers including 0 (0, 1, 2, 3, ...) together with the negatives of the non-zero...
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| Inch |
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In. |
An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ – a double prime) is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and...
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| Inches | ||||
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| Imperial unit system |
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Imperial unit |
Imperial units or the imperial system is a system of units, first defined in the British Weights and Measures Act of 1824, later refined (until 1959) and reduced. The system came into official use across the British Empire. By the late 20th century...
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| Joule | Joules |
The joule (symbol J), named for James Prescott Joule, is the derived unit of energy in the International System of Units. It is the energy exerted by the force of one newton acting to move an object through a distance of one metre. In terms of...
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| Kilogram |
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Kilograms |
The kilogram (symbol: kg) is the base unit of mass in the International System of Units (SI, from the French Le Système International d’Unités), which is the modern standard governing the metric system. The kilogram is defined as being equal to the...
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| Kilogramme | ||||
| Kilogrammes | ||||
| Kg | ||||
| Kelvin |
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Degree Kelvin |
The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. The Kelvin scale is a thermodynamic (absolute) temperature scale referenced to absolute zero, the theoretical absence of all thermal energy. By...
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| Degrees Kelvin | ||||
| °K | ||||
| Kelvins | ||||
| Kilobyte | Kbyte |
The kilobyte (derived from the SI prefix "kilo-", meaning 1,000) is a unit of digital information storage equal to either 1,000 bytes (10) or 1,024 bytes (2), depending on context.
It is abbreviated in a number of ways: KB, kB, K and Kbyte.
The...
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| ㎅ | ||||
| Kilobytes | ||||
| Katal | ㏏ |
The katal (symbol: kat) is the SI unit of catalytic activity. It is a derived SI unit for expressing quantity values of catalytic activity of enzymes and other catalysts. Its use is recommended by the General Conference on Weights and Measures and...
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| Kilobit | Kbit |
A kilobit is an expression of grouped bits meaning 1,000 (10) bits. Use of the term to denote a kibibit, although the most common use due to the nature of bits (binary digits), is deprecated and contrary to international standard.
The term 'kilobit'...
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| Leap year |
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Intercalary year |
A leap year (or intercalary year) is a year containing one extra day (or, in the case of lunisolar calendars, a month) in order to keep the calendar year synchronized with the astronomical or seasonal year.
For example, in the Gregorian calendar ...
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| Leap years | ||||
| Liter | Cubic decimetre |
The litre or liter (see spelling differences) is a unit of volume. There are two official symbols: the Latin letter L in lower and upper case (l and L). The lower case L is also often written as a cursive ℓ, though this symbol has no official...
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| Cubic decimeter | ||||
| Litre | ||||
| Liters | ||||
| Litres | ||||
| Luminance |
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The...
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| Length | Distance |
Length is the long dimension of any object. Not to be confused with Depth which is the property of the object that appears to go away from the observer. The length of a thing is the distance between its ends, its linear extent as measured from end...
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| Meter |
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Metre |
The metre (or meter) is the basic unit of length in the International System of Units (SI). Historically, the metre was defined by the French Academy of Sciences as the length between two marks on a platinum-iridium bar, which was designed to...
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| Meters | ||||
| Metres | ||||
| Mass |
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In physics, mass (from Ancient Greek: μᾶζα) commonly refers to any of three properties of matter, which have been shown experimentally to be equivalent: inertial mass, active gravitational mass and passive gravitational mass. In everyday usage, mass...
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| Mile |
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Miles |
A mile is a unit of length in a number of different systems. In contemporary English, a mile most commonly refers to the statute mile of 5,280 feet (1,760 yards, or 1,609.344 meters) or the nautical mile of 1,852 meters (6,076.12 ft). There are many...
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