Copy of `HowMany - Unit Dictionar`

The wordlist doesn't exist anymore, or, the website doesn't exist anymore. On this page you can find a copy of the original information. The information may have been taken offline because it is outdated.

HowMany - Unit Dictionar Category: Mathematics and statistics > Dictionary of unit measurements Date & country: 26/09/2008, USA Words: 1293

uncia
a Latin name for the fraction 1/12, subsequently used in many ways to represent a twelfth part. The Romans had no mathematical notation for fractions. When they needed to refer to a fractional part of anything, they would often state its nearest equivalent in unciae.

uncia
the Roman ounce, equal to about 27.2875 grams of 0.9625 ounce avoirdupois. There were 12 ounces in a Roman pound, and the word uncia means a 12th part; its name gives us the ounce, of course, and also the inch.

unit
a shorthand word for a variety of named 'units,' particularly the international unit in pharmacology.

unit (of blood)
a unit of volume for human blood and various blood components or products. A unit of whole blood is 450 milliliters, which is about 0.9510 U.S. pint. For components of blood, one unit is the amount of that substance that would normally be found in one unit of whole blood. The adult human body contains roughly 12 units of whole blood.

unit (of heroin)
a unit of mass or weight for heroin equal to exactly 700 grams (0.7 kilogram or about 1.543 pounds). This unit, standard in the southeast Asian drug trade, is also called the Asian unit in U.S. drug enforcement.

unit case
a conventional unit of sales volume in the U.S. soft drink industry. A unit case consists of soft drinks, syrup, powder, or whatever equivalent to 24 eight-ounce servings (6 quarts or about 5.678 liters).

urna
a Roman unit of volume equal to 4 congii, 24 sextarii, or 1/2 amphora. This is equivalent to about 12.75 liters (3.37 U.S. liquid gallons or 2.80 British Imperial gallons). The Latin word urna was also used more broadly to mean a jug, giving rise to the English word urn.

VAC
a common symbol for the voltage in an alternating current (AC) circuit (see var below for comments on alternating current). The SI does not allow symbols to be modified with additional information; instead of '12 VAC,' write 'AC 12 V.'

vagon
a traditional unit of mass or weight in countries of the former Yugoslavia. Originally considered to be the weight that could be carried by a wagon, the unit has been 'metrized' and is now defined to be equal to the dekatonne, that is, 10 metric tons or 22 046.23 pounds avoirdupois.

val
a symbol used in Europe, especially in Germany, for the equivalent weight.

var
a unit of the reactive electric power delivered by an alternating current (AC) circuit. In an AC circuit, the electric potential or voltage (measured in volts) and the current (in amperes) alternate direction, varying smoothly according to sine curves. In a purely resistive circuit, current is in phase with voltage. In a purely inductive circuit, t...

VDC
a common symbol for the voltage in a direct current (DC) circuit. In DC circuits, both voltage and current are constant. The SI does not allow symbols to be modified with additional information; instead of '12 VDC,' write 'DC 12 V.'

vedro
a traditional Russian unit of volume equal to 100 charki. The vedro is about 12.30 liters (3.249 U.S. liquid gallons or 2.706 British imperial gallons). In Bulgaria, the vedro has also been used informally as a name for the dekaliter (exactly 10 liters or 2.642 U.S. liquid gallons). The word vedro means a bucket.

verge
an old name for the yard, taken from the Latin word virga for a twig or stick. In modern French, verge is the customary word for the English yard.

vershok or verchok
a traditional Russian unit of distance equal to 1/16 arshin, 1.75 inches or 4.445 centimeters. The plural is vershki.

viertel
a traditional unit of volume in several European countries. Oddly, although the name means 'quarter' in German the traditional viertel is not really 1/4 of any other unit. The Danish viertel equals 8 pots or about 7.74 liters (2.04 U.S. liquid gallons or 1.70 British imperial gallons). In Switzerland the viertel is 40 schoppen, which is exactly 15 ...

viertel
a unit of volume for wine in Austria, equal to exactly 1/4 liter (250 milliliters) or about 8.45 U.S. fluid ounces.

violle
an obsolete unit of light intensity equal to 20.17 candelas. One violle is the intensity of a square centimeter of platinum, glowing at its melting temperature of 1769 °C (3216 °F). The unit is named for the French physicist Jules Violle (1841-1923), who proposed it in 1881; it was the first unit of light intensity that did not depend on ...

virgate
an old English unit of land area equal to 1/4 hide. This is roughly 30 acres or 12 hectares. The virgate was also called the yardland or yard of land.

viscosity grade (VG)
a commercial rating of industrial lubricants. The grade numbers are approximately equal to the kinematic viscosity of the lubricant in centistokes. A table is provided showing the range of viscosities acceptable for each grade under the current standard of the International Organization for Standardization (ISO).

vision
a term often used with a Snellen fraction in phrases such as '20/20 vision.'

volume unit (vu)
a unit used in telecommunications to describe the volume of a radio or television signal carrying complex information such as speech or music. These waves vary wildly in amplitude in order to represent the message they carry, so it is difficult to describe mathematically how large their 'average' amplitude is. To solve this problem, the American St...

water column (WC)
a notation seen in pressure measurements. See inch of water, centimeter of water, or millimeter of water.

water horsepower (whp or Whp)
a unit of power used in the U.S. primarily in rating pumps. If a pump has a capacity of Q gallons per minute and develops a pressure ('head') of P feet of head, then its power rating is QP/3956 water horsepower. This calculation assumes the density of water to be 8-1/3 pounds per U.S. gallon, which is approximately correct but not exact. As a resul...

watt hour (W•h)
a common metric unit of work or energy, representing the energy delivered at a rate of one watt for a period of one hour. This is equivalent to exactly 3.6 kilojoules (kJ) of energy, or about 3.412 141 Btu, 0.859 846 (kilogram) Calories, or about 2655 foot pounds.

watt year (W•yr)
a metric unit of energy, representing the energy delivered at a rate of one watt for a period of one year. The watt year, equal to about 31.5569 megajoules (MJ), is used in discussions of the rate of global warming.

wave or wavelength
a unit of relative distance equal to the length of a wave: this could be a light wave, a radio wave, or even an ordinary water wave. In communications engineering, the length of an antenna is often stated in waves. In optics, the surfaces of lenses and mirrors are required to be precisely polished to within a very small fraction of a wavelength of ...

werst
a German spelling, sometimes seen in English as well, for a Russian distance unit, the verst.

wey
a historic English unit. The word comes from the old English wæge, meaning weight, and originally the wey was a weight unit representing about two hundredweight. Later it came to be used as a volume unit for a variety of dry commodities. Its size varied. Roughly speaking, the wey represented about 40 bushels, 2 cubic yards, or 1.5 cubic meter...

whole note
a unit of relative time in music, also called a semibreve.

whole step, whole tone
alternate names for the step , a unit used in music to express the ratio in frequency between two tones.

Winchester bushel
the traditional British name for what is now the U.S. bushel; see bushel .

Winchester quart
an informal British unit of volume used for certain chemicals shipped in cylindrical, narrow-necked bottles. A Winchester quart originally held 2 British Imperial quarts (about 2.273 liters); now it generally holds exactly 2.5 liters. This unit is not related to the Winchester bushel, and the origin of its name is not known.

wine gallon
a former English unit of volume equal to 231 cubic inches. The wine gallon was adopted as the official gallon for liquid measurement in the United States, so now it is usually called the U.S. liquid gallon.

wineglass
an informal unit of volume used in U.S. bartending, equal to 4 (U.S.) fluid ounces or about 118.3 milliliters. This unit is the same as the traditional gill.

wineglassful
a unit of volume used in British food recipes. The wineglass holds 2.5 (British imperial) fluid ounces, 5 tablespoonfuls, 1/2 gill, or about 71.0 milliliters. One wineglassful is equal to 0.60 U.S. cup.

word
a unit of information in computer science, often representing the amount of data processed by a computer in a single instruction. The size of a word varies with the computer system; it was usually 32 bits (4 bytes) or 64 bits (8 bytes) on mainframe computers but is usually 16 bits (2 bytes) in modern microprocessors. Sometimes a shortword is 2 byte...

working level (WL)
a unit of radiation exposure used for measuring exposure to radon gas in the U.S. One working level represents a concentration of short-lived radon decay products in one liter of air resulting in the ultimate emission of 1.3 x 10⁵ MeV or 20.8 nanojoules (nJ) of energy. Exposures are measured in working level months (WLM). Cum...

wrench sizes
fixed wrenches in the U.S. are sized in fractions of an inch or in multiples of 1/4 inch, while metric wrenches are sized in millimeters.

WS
German abbreviation for Wassersäule, water column, seen in pressure measurements. See centimeter of water or millimeter of water.

wyde
a unit of information in computer science, equal to 2 bytes or 16 bits. This name for the 'double byte' was proposed by the American computer scientist Donald Knuth. It has achieved at least some use, but it is not well established.

yard (yd)
a cubic yard (about 764.555 liters). Bulk commodities like sand or topsoil are often sold by the 'yard.'

yard of ale
a traditional Scottish measure of volume. A yard of ale is roughly 2.5 pints (1.4 liters) served in a slender, yard-tall glass.

yard of land, yardland
one of several traditional units of area in old England; a 'yard of land' sometimes meant a virgate (roughly 30 acres) and sometimes a rood (1/4 acre).

yoke
another name for a pair. The yoke is used in describing teams of animals, especially oxen, used to pull plows or wagons.

zak
a Dutch unit of volume, now interpreted as a metric unit equal to the hectoliter (100 liters). The hectoliter is equivalent to 26.417 U.S. gallons, 21.999 British imperial gallons, or 3.5315 cubic feet. This is a metric version of the British sack.

Zhubov scale
a scale for reporting ice coverage of polar seas; see ball.

zoll
the traditional German inch, equal to 1/12 fuss. Originally the zoll was equal to 1.037 inches (about 2.634 centimeters). In Switzerland, it is now considered a metric unit equal to exactly 3 centimeters (1.1811 inches). There's no change in the plural.

a or A
shortened version of am or AM in a statement of time (see below).

A
a symbol for international standard paper sizes, followed by the size number, as in A4 for a standard business-letter sheet. A table of sizes is provided. 'A' is also the SI symbol for the ampere (see below).

A*
see 'angstrom star' below.

B
a symbol for international standard paper sizes, followed by the size number, as in B4. A table of sizes is provided.

B/D
symbol for barrels of oil per day (see barrel above), a unit used in the energy industry to measure the rate at which oil is pumped from a well.

C
the Roman numeral 100, sometimes used as a unit of quantity or as a prefix meaning 100, as in Cwt (hundredweight) or CCF (100 cubic feet).

C
a symbol for international standard paper sizes, followed by the size number, as in C4. The C series of sizes is used primarily for envelopes. A table of sizes is provided.

C
a unit of relative current for batteries. For a particular battery, a current of 1C is a current in amperes numerically equal to the rated capacity of the battery in ampere hours. In other words, a 1C current will completely charge or discharge the battery in one hour.

D-
an incorrect symbol for the metric prefix deka- or deca-, seen in combinations such as DL (dekaliter) or DTH (dekatherm). The correct prefix is da-.

e
a mathematical unit used as the base of 'natural' logarithms and exponentials. The real number e is irrational, which means that its decimal expansion is infinite and non-repeating. To 25 significant digits e equals 2.718 281 828 459 045 235 360 287. Of the many properties of this number, the most important is that the rate of change in the functio...

F
see farad or Fujita-Pearson scale, below.

f number
see f ratio, below.

f stop
see f ratio, above.

g/g
a symbol for 'gram per gram', a unit of mass concentration. For example, a concentration of 0.02 g/g, or 2% g/g, means that the substance being measured comprises 2% of the mass of the mixture in which it is found. This symbol is equivalent to the traditional symbol w/w.

g/kg
a symbol for 'gram per kilogram', a unit of mass concentration equal to 1 per mill (1 part per thousand). 1 g/kg also equals 0.1% g/g or 0.1% w/w.

g/t
symbol for grams per tonne (metric ton), a unit of proportion equal to 0.001 g/kg or 1 part per million by mass. This unit is used, for example, in stating the concentration of gold, silver, or other minerals in ores.

h
Planck's constant, equal to approximately 6.626 068 96 x 10^-34 joule second, a fundamental constant of physics also used as a unit of 'action' or of angular momentum in particle physics. The unit was defined by the German physicist Max Planck (1858-1947), who showed in 1900 that at atomic and subatomic scales energy occurs in...

köddi
a traditional Arabic unit of volume, equal to about 4/3 British imperial gallon or 7.58 liters.

légua or legoa
the Portuguese league, equal to 3 milhas (Portuguese miles). This is equal to about 3.836 statute miles or 6174.1 meters.

M
the Roman numeral 1000, sometimes used in symbols to indicate a thousand, as in Mcf, a traditional symbol for 1000 cubic feet. Given the widespread use of M to mean one million, this older use of M to mean 1000 is very confusing and should be scrapped.

mål
a Norwegian word for 'measure,' mål has been used as a name for various traditional Norwegian units. As a land measure, the mål is currently defined to be the same as the dekare, that is, exactly 1000 square meters (0.1 hectare or 0.2471 acre). The mål has also been used as a unit of volume equal to the dekaliter (10 liters).

m/m
an abbreviation for 'by mass,' used in chemistry and pharmacology to describe the concentration of a substance in a mixture or solution. 2% m/m means that the mass of the substance is 2% of the total mass of the solution or mixture.

N
a unit of refractive index sometimes used in atmospheric science. The index of refraction of the atmosphere is only slightly greater than 1. The value of the index in N units is the number of millionths by which the index exceeds one; that is, an index of refraction n is equivalent to (n - 1) x 10⁶ N units.

o'clock
an informal angular measure that works by describing an angle in terms of the face of a standard (12-hour) clock. Each hour 'o'clock' spans an angle of 30°, so '4 o'clock' means an angle of 120° measured clockwise from dead ahead or some other agreed-upon point of reference.

P or p
a common short form of PM or pm (see below), used in statements of time.

pé
the traditional Portuguese foot, equal to 12 polegadas or about 33.324 centimeters (13.12 inches).

q-
a symbol for the Latin quaque, 'every,' often used in medical prescriptions and orders. The symbol is used in combinations such as q8h, 'every 8 hours,' or q2d, 'every other day.'

q-
a former German prefix meaning quadrat-, 'square,' seen in combinations such as qm (Quadratmeter or square meter) and qkm (Quadratkilometer or square kilometer). The SI does not allow use of this symbol; it is rarely used in current works but often seen in older documents.

Q
a metric unit of distance equal to exactly 0.25 millimeter (9.8425 mils) used by typographers and page designers in Japan, in Germany, and in other countries in preference to the traditional point . One Q is equal to about 0.71 point, a little more or less depending on the exact definition of the point. This unit is also spelled kyu.

q.h.
abbreviation for the Latin quaque hora, once an hour, a unit of frequency traditionally used in medical prescriptions. This notation is often modified for a lesser frequency by imbedding a number of hours in the middle, as in q.3h., every three hours.

Q unit
a unit of heat energy equal to one quintillion (10¹⁸) Btu, 1000 quads, or about 1.055 zettajoules (ZJ).

Réaumur
a temperature scale; see degree Réaumur.

tønde
the Danish word for 'barrel,' traditionally used as a unit of volume equal to 144 pots or about 139 liters. The tønde holds 30.6 British imperial gallons, making it comparable to the barrel Similarly, one of the meanings of the German word Tonne is 'barrel.'

tønde land
a traditional Danish unit of land area, originally the area that could be planted with a tønde of seed. The tønde land equals 14 000 square alen, which is about 5516 square meters, 0.5516 hectare, or 1.363 acre.

t'sun
a unit of relative distance used in acupuncture. One t'sun is the distance between the two outer folds in the bent middle finger, or (according to some sources) the width of the thumb. This is a personal unit, different for each person and used to locate acupuncture points on that person's body. The unit is also spelled cun and is sometimes called ...

u
a common replacement for the Greek letter µ as a symbol for the micron or micrometer. The correct symbol for this unit is µm.

U
a commercial unit of thermal conductance (heat flow). The U factor, as it is also called, is the conductance through an insulator as measured in Btu's of energy conducted times inches of thickness per hour of time per square foot of area per °F of temperature difference between the two sides of the material. The U factor is numerically equal t...

U
a unit of distance used to measure the height of the standard racks in which audio, video, or computer components are mounted. 1U is equal to 1.75 inches (44.45 millimeters), so that, for example, a 2U component is 3.5 inches high, and a 22U rack houses a stack of components 38.5 inches high.

U
usual symbol for the enzyme unit.

U
German symbol for a turn or revolution (Umdrehung), usually seen in combinations such as U/min, the German equivalent of the English symbol rpm for revolutions per minute.

V
the SI symbol for the volt (see below).

W
the SI symbol for the watt (see below).

w/w
an abbreviation for 'by weight,' used in chemistry and pharmacology to describe the concentration of a substance in a mixture or solution. Properly speaking, 2% w/w means that the mass of the substance is 2% of the total mass of the solution or mixture. The metric symbol g/g has the same meaning as w/w.

y/o
a common symbol for 'years old.'

z
symbol for redshift, a unit of relative distance used in astronomy.