 mahnd

a traditional Arab weight unit equal to about 2.04 pounds or 925 grams.
 mål

a Norwegian word for "measure," As a land measure, the mål is the same as the
dekare, that is, exactly 1000 square meters (0.1 hectare or 0.2471 acre). As a
unit of volume, it is equal to the dekaliter (10 liters).
 mandel

a traditional German unit of quantity equal to 15.
 man hour

a common unit of labor equal to the work of one person for one hour. The less
restrictive term person hour is gradually coming into use.
 marathon

an unit of distance used in athletics. It is exactly 42 195 meters (about half
an inch longer than 26 miles 385 yards). Invented for the first modern Olympic
Games at Athens in 1896, the marathon recalls a run made in 490 BC by a Greek
soldier to bring to Athens the news of the Greek victory over the Persians at
the Battle of Marathon.
 marla

a unit of area in Pakistan. It was standardized, and equal to the
square rod, 272.25 square feet, 30.25 square yards, or 25.2929 square meters.
 masha

a traditional unit of mass in India and Pakistan, standardized under British
rule as 15 grains, 1/12 tola, or about 0.972 gram. In Pakistan, the unit is
still used sometimes for the weight of precious metals.
 maß (mass)

a unit of volume for beer in Germany and Austria, usually equal to one liter
today. The traditional Bavarina maß was about 1.07 liters.
 maund

a unit of weight in India and throughout South Asia. The maund varied
considerably, but during the period of British rule in India it was
standardized at about 82.286 pounds or 37.3242 kilograms. The maund is
divided into 40 seers. Since 1980, Pakistan has used a metric version of the
maund qual to exactly 40 kilograms (88.185 pounds), thus making the seer equal
to the kilogram.
 measurement ton

a unit of volume used for measuring the cargo of a ship, truck, train, or other
freight carrier, equal to exactly 40 cubic feet, or approximately 1.1326 cubic
meters. This unit was traditionally called a freight ton, but that term now
means a metric ton of freight in most international usage.
 mega

a metric prefix meaning 10^{6}, or one million. It is derived from the
Greek word for large, megas.
 megohm

a common unit of electric resistance equal to one million ohms. It
actually called as megaohm.
 meile

A traditional distance unit in German speaking countries, the meile is much
longer than the mile units of western Europe. Typically the meile was equal to
4000 klafters (fathoms) or 24 000 fuß (German feet), equals to 7586 meters
(4.714 miles) In Austria ; 4.6805 miles or 7532.5 meters in northern
Germany.
 melchior

a huge bottle of champagne, holding about 18 liters.
 meter or metre (m)

the metric and SI base unit of distance. Originally, the meter was designed to
be one tenmillionth of a quadrant, the distance between the Equator and the
North Pole. For a long time, the meter was precisely defined as the
length of an actual object, a bar kept at the International Bureau of Weights
and Measures in Paris. However, the SI base units have been redefined in
abstract terms so they can be reproduced to any desired level of accuracy in a
wellequipped laboratory. The 17th General Conference on Weights and Measures
in 1983 defined the meter as that distance that makes the speed of light in a
vacuum equal to exactly 299 792 458 meters per second.

The meter is equal to approximately 1.093 613 3 yards, 3.280 840 feet, or
39.370 079 inches. Its name comes from the Latin metrum and the Greek metron,
both meaning "measure." The unit is spelled meter in the U.S. and metre
in Britain.
 metric carat

the currently called carat, equal to exactly 200 milligrams.
 metric grain

a unit of mass sometimes used by jewelers, equal to 50 milligrams or 1/4
carat. It is often used for pearls and is sometimes called the pearl
grain.
 metric horsepower

a unit of power, defined to be the power required to raise a mass of 75
kilograms at a velocity of 1 meter per second. It is approximately 735.499
watts or 0.986 32 horsepower.
 metric mile

an informal unit of distance used mostly in athletics. The metric mile is equal
to 1500 meters or 1.5 kilometers (approximately 0.932 057 statute mile or
4921.26 feet). In U.S. high school competition the term is sometimes used for a
race of 1600 meters (0.994 194 miles or 5249.34 feet).
 metric pound

an informal name for a mass of 500 grams (0.5 kilogram or 1.1023 pound).
 metric ton

an alternate name for the tonne.
 micro (µ or mc or u)

a metric prefix meaning 10^{6} (one millionth). The prefix comes from
the Greek prefix mikro, meaning small. In print the prefix is
sometimes abbreviated mc or u when the Greek letter mu (µ) is not available.
 micromicro (µµ)

an obsolete metric prefix denoting 10^{12}. The prefix has been
replaced by pico (p).
 miglio

the traditional Italian mile. The miglio equals 1628 yards, which is 0.925
English mile or about 1488.6 meters. This is 32 yards (29.3 meters) shorter
than the classical Roman mile.
 mil

a unit of distance equal to 0.001 inch: a "milliinch".

One mil is exactly 25.4 microns, just as one inch is exactly 25.4 millimeters.
 mile

a traditional unit of distance. The word comes from the Latin word for 1000, mille.
In medieval Britain, several mile units were used, including a mile of
5000 feet (1524 meters). The modern mile defined as 8 furlongs (1609
meters), there are longer miles such as the French mille
(1949 meters), the Scottish mile (1814 meters) and the Irish mile (2048
meters). In 1592, Parliament in England defined the statute mile
to be 8 furlongs, 80 chains, 320 rods, 1760 yards or 5280 feet. The statute
mile is exactly 1609.344 meters. In athletics, races of 1500 or 1600 meters are
often called metric miles.
 mile per gallon

the unit used in the United States to measure the fuel efficiency of
motor vehicles. 1 mile per gallon equals about 0.4252 kilometers per liter.
 mile per hour

a traditional unit of velocity. One mile per hour equals exactly 22/15 feet per
second, 1.609 kilometers per hour (km/h), or exactly 0.447 04 meter per second
(m/s).
 milha

the Portuguese mile, 2282.75 yards (1.297 statute miles or 2087.3 meters).
 milla

the Spanish mile, equal to 5000 pies (Spanish feet) or 8 estadios. This
is about 1392 meters, 4567 feet, or 0.865 statute mile.
 mille

the traditional French mile, equal to 1000 toises. This is equal to about
6394.4 feet, 1.211 statute mile, or 1949 meters. In modern France, the mille
sometimes means the nautical mile (mille marin ), equal to exactly 1852
meters.
 millenary

a unit of quantity equal to 1000.
 millennium

a traditional unit of time equal to 1000 years. The plural is millennia
or sometimes millenniums.
 milli (m)

a metric prefix meaning 0.001 (one thousandth). The prefix was coined from the
Latin number mille, one thousand.
 milliliter (ml or mL)

common metric unit of volume. One milliliter equals 0.001 liter, exactly one
cubic centimeter (cm^{3} or cc), or approximately 0.061 023 7 cubic
inch or 16.231 U.S. minims (see below). The milliliter is used almost entirely
for measuring the volumes of liquids, with solids being measured in cubic
centimeters.
 millimass unit

a unit of mass equal to 0.001 atomic mass unit, used in physics and chemistry.
This unit is also called the millidalton (mDa).
 millimeter (mm)

a very common metric unit of distance. One millimeter equals 0.001 meter, 0.1
centimeter, about 0.039 370 inch, or 39.370 mils.
 millisecond (ms or msec)

a common unit of time equal to 0.001 second.
 mina

a historic unit of weight, originating in Babylonia and used throughout the
eastern Mediterranean. It varied quite a bit. In Babylonian times it was a
large unit, roughly 2 pounds, almost as much as a kilogram. The Hebrew mina,
frequently mentioned in the Bible, is estimated at 499 grams (1.10 pounds). The
Greek mina was equal to 100 drachmai or 431 grams (0.95 pound). In Biblical
times, the mina was equal to 60 shekels, and there were 60 minas in a talent.
 minim

a traditional unit of volume used for very small quantities of liquids. In
pharmacy, the term drop traditionally meant the same thing as 1 minim.
The word comes from the Latin minimus, small.

minim is also a unit of relative time in music equal to 1/2 whole note (a half
note) or 1/4 breve.
 minute (')

a historic unit of proportion equal to 1/60. A 60th part was called a pars
minuta prima ("first small part") of the whole. For smaller fractions,
a 60th part was divided into 60 smaller parts, each called a pars
minuta secunda ("second small part"). The minuta prima has
come down to us as "minute," the minuta secunda is our "second," and
the prima leads to the traditional symbol ' being called a "prime."

as a unit of time, minute equal to 60 seconds or to 1/60 hour.

as a unit of angular measure, minute equal to 60 arcseconds or to 1/60
degree. This unit is often called the arcminute to distinguish
it from the minute of time. There are 21 600 arcminutes in a circle.
 minutum

a unit of time equal to 1/10 hour in medieval times, or 6 minutes in modern
terminology. This unit was divided into 4 moments.
 minyan

a traditional Hebrew unit of quantity equal to 10, the number of males aged 13
or over required for a Jewish worship service.
 mkono

a traditional unit of distance in East Africa, standardized under British rule
as 1/2 yard (18 inches, or 45.72 centimeters). This unit is an African version
of the cubit.
 mmHg

symbol for the millimeter of mercury, a unit of pressure equal to 133.3
pascals.
 module

a unit of volume for raw cotton in the U.S. When cotton is harvested, machinery
is used to compact it into bundles called modules for transportation to the
gin. A cotton module is 8 ft by 8 ft by 20 ft, or 1280 cubic feet (about 36.25
cubic meters).
 moiety

another name for a half, from the French moitié.
 molad

Hebrew name for the lunar (synodic) month, 29.530 59 days, is crucial in the
regulation of the Jewish lunisolar calendar.
 mole (mol)

the SI base unit of the amount of a substance. Moles measure the
actual number of atoms or molecules in an object. An alternate name is gram
molecular weight .
 moment

a medieval unit of time equal to 1/40 hour or 1.5 minutes. This meaning has
come down to us only as "a brief interval of time." The moment was divided into
12 ounces of 7.5 seconds each.
 month

a unit of time marked by the revolution of the Moon around the Earth. The lunar
month is defined as the average interval between two successive
moments of New Moon. Astronomers call this period the synodic month.
Its length is 29.530 59 days.

a civil unit of time equal to approximately 1/12 year, but varying from 28 to
31 days. A solar year equals approximately 12.368 lunar months. The large
fraction in this number makes it difficult to design a calendar with a whole
number of months in each year.
 morgen

a traditional unit of land area in Northern Europe. "Morgen" means
"morning," likely the unit arose as the area a yoke of oxen could plow in
one morning. The Dutch morgen, also used in Dutch colonies including old New
York, equals about 2.10 acres or 0.850 hectare. In Austria and southern
Germany, the morgen was often the same as a joch, defined to be 0.5755
hectare or about 1.422 acres.
 MT

a common U.S. abbreviation for the metric ton or tonne (1000 kilograms).
 mu or mou

a traditional unit of land area in China. The traditional mu is about 675
square meters or 800 square yards. However, the colonial customs authorities
used a larger mu equal to 8273.75 square feet, 919.3 square yards, or 768.65
square meters. In modern China, the mu is often reckoned to be exactly 1/15
hectare, which is 666.667 square meters or 797.327 square yards.
 mud

a traditional Dutch unit of volume for grains and other dry commodities.
Originally varying from market to market, the unit was declared equal to the
hectoliter (about 3.5315 cubic feet or 2.838 U.S. bushels) when the metric
system was introduced in the Netherlands. With this definition it is still in
use.
