Weights and Measures Units - Table

acoustic ohm

cgs unit of acoustic impedance (the ratio of sound pressure on a surface to sound flux through the surface)

acre

traditional English land measure; 1 acre = 4,840 sq yd (4,047 sq m or 0.4047 ha)

acre-foot

unit sometimes used to measure large volumes of water such as reservoirs; 1 acre-foot = 1,233.5 cu m/43,560 cu ft

astronomical unit

unit (symbol AU) equal to the mean distance of the earth from the sun: 149,597,870 km/92,955,808 mi

atmosphere

unit of pressure (abbreviation atm); 1 standard atmosphere = 101,325 Pa

barn

unit of area, especially the cross-sectional area of an atomic nucleus; 1 barn = 10^-28 sq m

barrel

unit of liquid capacity; the volume of a barrel depends on the liquid being measured and the country and state laws. In the United States, 1 barrel of oil = 42 gal (159 l/34.97 imperial gal), but for federal taxing of fermented liquor (such as beer), 1 barrel = 31 gal (117.35 l/25.81 imperial gal). Many states fix a 36-gallon barrel for cistern measurement and federal law uses a 40-gallon barrel to measure 'proof spirits.' 1 barrel of beer in the UK = 163.66 l (43.23 U.S. gal/36 imperial gal)

base box

imperial unit of area used in metal plating; 1 base box = 20.232 sq m/31,360 sq in

baud

unit of electrical signaling speed equal to 1 pulse per second

brewster

unit (symbol B) for measuring reaction of optical materials to stress

British thermal unit

imperial unit of heat (symbol Btu); 1 Btu = approximately 1,055 J

bushel

measure of dry and (in the UK) liquid volume. 1 bushel (struck measure) = 8 dry U.S. gallons (64 dry U.S. pt/35.239 l/2,150.42 cu in). 1 heaped U.S. bushel = 1.278 bushels, struck measure (81.78 dry pt/45.027 l/2,747.715 cu in), often referred to as 11/4 bushels, struck measure. In the UK, 1 bushel = 8 imperial gallons (64 imperial pt); 1 UK bushel = 1.03 U.S. bushels

cable

unit of length used on ships, taken as 1/10 of a nautical mile (185.2 m/607.6 ft)

calorie

cgs unit of heat, now replaced by the joule; 1 calorie = 4.1868 J

carat

unit for measuring mass of precious stones; 1 carat = 0.2 g/0.00705 oz

carat

unit of purity in gold; pure gold is 24-carat

carcel

obsolete unit of luminous intensity

cental

name for the short hundredweight; 1 cental = 45.36 kg/100 lb

chaldron

obsolete unit measuring capacity; 1 chaldron = 1.309 cu m/46.237 cu ft

clausius

in engineering, a unit of entropy; defined as the ratio of energy to temperature above absolute zero

cleanliness unit

unit for measuring air pollution; equal to the number of particles greater than 0.5 µm in diameter per cu ft of air

clo

unit of thermal insulation of clothing; standard clothes have insulation of about 1 clo, the warmest have about 4 clo per 2.5 cm/1 in of thickness

clusec

unit for measuring the power of a vacuum pump

condensation number

in physics, the ratio of the number of molecules condensing on a surface to the number of molecules touching that surface

cord

unit for measuring the volume of wood cut for fuel; 1 cord = 3.62 cu m/128 cu ft, or a stack 2.4 m/8 ft long, 1.2 m/4 ft wide and 1.2 m/4 ft high

crith

unit of mass for weighing gases; 1 crith = the mass of 1 liter of hydrogen gas at standard temperature and pressure

cubit

earliest known unit of length; 1 cubit = approximately 45.7 cm/18 in, the length of the human forearm from the tip of the middle finger to the elbow

curie

former unit of radioactivity (symbol Ci); 1 curie = 3.7 × 10¹⁰ becquerels

dalton

international atomic mass unit, equivalent to 1/12 of the mass of a neutral carbon-12 atom

darcy

cgs unit (symbol D) of permeability, used mainly in geology to describe the permeability of rock

darwin

unit of measurement of evolutionary rate of change

decontamination factor

unit measuring the effectiveness of radiological decontamination; the ratio of original contamination to the radiation remaining

demal

unit measuring concentration; 1 demal = 1 gram-equivalent of solute in 1 cu dm of solvent

denier

unit used to measure the fineness of yarns; 9,000 m of 15 denier nylon weighs 15 g/0.5 oz

diopter

optical unit measuring the power of a lens; the reciprocal of the focal length in meters

dram

unit of apothecaries' measure; 1 dram = 60 grains/3.888 g

dyne

cgs unit of force; 10⁵ dynes = 1 N

einstein unit

unit for measuring photoenergy in atomic physics

eotvos unit

unit (symbol E) for measuring small changes in the intensity of the earth's gravity with horizontal distance

erg

cgs unit of work; equal to the work done by a force of 1 dyne moving through 1 cm

erlang

unit for measuring telephone traffic intensity; for example, 90 minutes of carried traffic measured over 60 minutes = 1.5 erlangs ('carried traffic' refers to the total duration of completed calls made within a specified period)

fathom

unit of depth measurement in mining and seafaring; 1 fathom = 1.83 m/6 ft

finsen unit

unit (symbol FU) for measuring intensity of ultraviolet light

fluid ounce

measure of capacity; equivalent in the United States to 1/16 of a pint (1/20 of a pint in the UK and Canada)

foot

imperial unit of length (symbol ft), equivalent to 0.3048 m

foot-candle

unit of illuminance, replaced by the lux; 1 foot-candle = 10.76391 lux

foot-pound

imperial unit of energy (symbol ft-lb); 1 ft-lb = 1.356 joule

frigorie

unit (symbol fg) used in refrigeration engineering to measure heat energy, equal to a rate of heat extraction of 1 kilocalorie per hour

furlong

unit of measurement, originating in Anglo-Saxon England, equivalent to 201.168 m/220 yd

galileo

unit (symbol Gal) of acceleration; 1 galileo = 10^-2 m s^-2

gallon

imperial liquid or dry measure subdivided into 4 quarts or 8 pints; 1 U.S. gal = 3.785 l; 1 imperial gal = 4.546 l

gauss

cgs unit (symbol) of magnetic flux density, replaced by the tesla; 1 gauss = 1 × 10^-4 tesla

gill

imperial unit of volume for liquid measure; equal to 1/4 of a pint (in the United States, 4 fl oz/0.118 l; in the UK, 5 fl oz/0.142 l)

grain

smallest unit of mass in the three English systems of measurement (avoirdupois, troy, apothecaries' weights) used in the United States and UK; 1 grain = 0.0648 g

hand

unit used in measuring the height of a horse from front hoof to shoulder (withers); 1 hand = 10.2 cm/4 in

hardness number

unit measuring hardness of materials. There are many different hardness scales: Brinell , Rockwell , and Vickers scales measure the degree of indentation or impression of materials; Mohs ' scale measures resistance to scratching against a standard set of minerals

hartree

atomic unit of energy, equivalent to atomic unit of charge divided by atomic unit of length; 1 hartree = 4.850 × 10^-18 J

haze factor

unit of visibility in mist or fog; the ratio of brightness of mist compared with that of the object

Hehner number

unit measuring concentration of fatty acids in oils; a Hehner number of 1 = 1 kg of fatty acid in 100 kg of oil or fat

hide

unit of measurement used in the 12th century to measure land; 1 hide = 60-120 acres/25-50 ha

horsepower

imperial unit (abbreviation hp) of power; 1 horsepower = 746 W

hundredweight

imperial unit (abbreviation cwt) of mass; 1 cwt = 45.36 kg/100 lb in the United States and 50.80 kg/112 lb in the UK

inch

imperial unit (abbreviation in) of linear measure, 1/12 of a ft; 1 in = 2.54 cm

inferno

unit used in astrophysics for describing the temperature inside a star; 1 inferno = 1 billion K (degrees Kelvin )

iodine number

unit measuring the percentage of iodine absorbed in a substance, expressed as grams of iodine absorbed by 100 grams of material

jansky

unit used in radio astronomy to measure radio emissions or flux densities from space; 1 jansky = 10^-26 Wm^-2 Hz^-1. Flux density is the energy in a beam of radiation which passes through an area normal to the beam in a single unit of time. A jansky is a measurement of the energy received from a cosmic radio source per unit area of detector in a single time unit

kayser

unit used in spectroscopy to measure wave number (number of waves in a unit length); a wavelength of 1.0 cm has a wave number of 1 kayser

knot

unit used in navigation to measure a ship's speed; 1 knot = 1 nautical mile per hour, or about 1.15 miles per hour

league

obsolete imperial unit of length; 1 league = 3 nautical mi/5.56 km or 3 statute mi/4.83 km

light-year

unit used in astronomy to measure distance; the distance traveled by light in one year, approximately 9.46 × 10¹² km/5.88 × 10¹² mi

mache

obsolete unit of radioactive concentration; 1 mache = 3.7 × 10^-7 curies of radioactive material per cu m of a medium

maxwell

cgs unit (symbol Mx) of magnetic flux, the strength of a magnetic field in an area multiplied by the area. 1 maxwell = 10^-8 weber

megaton

measurement of the explosive power of a nuclear weapon; 1 megaton = 1 million tons of trinitrotoluene (TNT)

mil

(a) one-thousandth of a liter; contraction of the word milliliter; (b) imperial measure of length, equal to one-thousandth of an inch; also known as the thou

mile

imperial unit of linear measure; 1 statute mile = 1.60934 km/5,280 ft, and 1 international nautical mile = 1.852 km/6,076 ft

millimeter of mercury

unit of pressure (symbol mmHg) used in medicine for measuring blood pressure

morgan

arbitrary unit used in genetics; 1 morgan is the distance along the chromosome in a gene that gives a recombination frequency of 1%

nautical mile

unit of distance used in navigation, equal to the average length of 1 minute of arc on a great circle of the earth; 1 international nautical mile =1.852 km/6,076 ft

neper

unit used in telecommunications; gives the attenuation of amplitudes of currents or powers as the natural logarithm of the ratio of the voltage between two points or the current between two points

oersted

cgs unit (symbol Oe) of magnetic field strength, now replaced by amperes per meter (1 Oe = 79.58 amp per m)

ounce

unit of mass, : of a pound avoirdupois, equal to 437.5 grains/28.35 g; or 14.6 pound troy, equal to 480 grains/31.10 g

parsec

unit (symbol pc) used in astronomy for distances to stars and galaxies; 1 pc = 3.262 light-years, 2.063 × 10⁵ astronomical units, or 3.086 × 10¹³ km

peck

obsolete unit of dry measure, equal to 8 imperial quarts or 1 quarter bushel (8.1 l in the United States or 9.1 l in the UK)

pennyweight

imperial unit of mass; 1 pennyweight = 24 grains = 1.555 × 10^-3 kg

perch

obsolete imperial unit of length; 1 perch = 51/2 yards = 5.029 m, also called the rod or pole

pint

imperial unit of liquid or dry measure; in the United States, 1 liquid pint = 16 fl oz/0.473 l, while 1 dry pint = 0.551 l; in the UK, 1 pt =20 fl oz, 1/2 quart, 1/8 gal, or 0.568 l

point

metric unit of mass used in relation to gemstones; 1 point = 0.01 metric carat = 2 × 10^-3 g

poise

cgs unit of dynamic viscosity; 1 poise = 1 dyne-second per sq cm

pound

imperial unit (abbreviation lb) of mass; the avoirdupois pound or imperial standard pound = 0.45 kg/7,000 grains, while the pound troy (used for weighing precious metals) = 0.37 kg/5,760 grains

poundal

imperial unit (abbreviation pdl) of force; 1 poundal = 0.1383 newton

quart

imperial liquid or dry measure; in the United States, 1 liquid quart = 0.946 l, while 1 dry quart = 1.101 l; in the UK, 1 quart =2 pt/1.137 l

rad

unit of absorbed radiation dose, replaced in the SI system by the gray; 1 rad = 0.01 joule of radiation absorbed by 1 kg of matter

relative biological effectiveness

relative damage caused to living tissue by different types of radiation

rood

imperial unit of area; 1 rood =1/4 acre = 1,011.7 sq m

roentgen

unit (symbol R) of radiation exposure, used for X- and gamma rays

rydberg

atomic unit of energy; 1 rydberg = 2.425 × 10^-18 J

sabin

unit of sound absorption, used in acoustical engineering; 1 sabin = absorption of 1 sq ft (0.093 sq m) of a perfectly absorbing surface

scruple

imperial unit of apothecaries' measure; 1 scruple = 20 grains = 1.3 × 10^-3 kg

shackle

unit of length used at sea for measuring cable or chain; 1 shackle = 15 fathoms (90 ft/27 m)

slug

obsolete imperial unit of mass; 1 slug = 14.59 kg/32.17 lb

snellen

unit expressing the visual power of the eye

sone

unit of subjective loudness

standard volume

in physics, the volume occupied by 1 kilogram molecule (molecular mass in kilograms) of any gas at standard temperature and pressure; approximately 22.414 cu m

stokes

cgs unit (symbol St) of kinematic viscosity; 1 stokes = 10^-4 m² s^-1

stone

imperial unit (abbreviation st) of mass; 1 stone = 6.35 kg/14 lb

strontium unit

measures concentration of strontium-90 in an organic medium relative to the concentration of calcium

tex

metric unit of line density; 1 tex is the line density of a thread with a mass of 1 gram and a length of 1 kilometer

tog

measure of thermal insulation of a fabric, garment, or quilt; the tog value is equivalent to 10 times the temperature difference (in °C) between the two faces of the article, when the flow of heat across it is equal to 1 W per sq m

ton

1 unit of mass; the long ton ( UK ) = 1,016 kg/2,240 lb; 1 short ton (United States) = 907 kg/2,000 lb; 1 metric ton = 1000 kg/2205 lb

yard

imperial unit (symbol yd) of length, equivalent to 0.9144 m/3 ft