The symbol for the meter. A metric unit of length.

mega

Symbol: M

A metric prefix equivalent to 10^{6} (1 000 000)

megagram

Symbol: Mg

A metric unit of mass equivalent to 10^{6} (1 000 000) grams.

megaliter

Symbol: Ml

Alternate symbols: ML

A metric unit of volume equivalent to 10^{6} (1 000 000) liters.

megameter

Symbol: Mm

A metric unit of length equivalent to 10^{6} (1 000 000) meters.

meter

Symbol: m

The base unit of length for the metric system and the International System of Units (SI). Defined as the exact distance light travels in an absolute vacuum in 1/299 792 458 of a second.

Originally, in 1791, the meter was defined as 1/10 000 000 of the distance between the equater and the North Pole through Paris. Then in 1889 and lasting until 1960 the meter was defined as the exact length of a metal bar kept under certain conditions. In 1960 the definition changed again to be 1 650 763.73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum. Then finally in 1983 the definition changed to what we use today.

Of course many scientists are not completely happy, and the definition may change yet again, possibly to 1 579 800.298 728 ± 0.000 039 wavelengths of Helium-Neon laser light in a vacuum, as that is the current delineated value.

metr

Symbol: m

An alternate spelling for the meter. Common in languages such as Czech, Polish, Russian, and Ukranian.

metras

Symbol: m

The Lithuanian spelling for the meter.

metre

Symbol: m

A common French spelling for the meter. Common in Britain, Australia, Canada, New Zealand, and France.

metri

Symbol: m

The Finnish spelling for the meter.

metro

Symbol: m

An alternate spelling for the meter. Common in languages such as Basque, Italian, Portuguese, and Spanish.

Mg

The symbol for the megagram, a metric unit of mass equal to 1 000 000 grams.

mg

The symbol for the milligram, a metric unit of mass equal to 0.001 grams.

micro

Symbol: µ

Alternate symbols: u

A metric prefix equivalent to 10^{-6} (0.000 001)

microgram

Symbol: µg

Alternate symbols: ug

A metric unit of mass equivalent to 10^{-6} (0.000 001) grams.

microliter

Symbol: µl

Alternate symbols: µL, ul, uL

A metric unit of volume equivalent to 10^{-6} (0.000 001) liters.

micrometer

Symbol: µm

Alternate symbols: um

A metric unit of length equivalent to 10^{-6} (0.000 001) meters.

milli

Symbol: m

A metric prefix equivalent to 0.001

milligram

Symbol: mg

A metric unit of mass equivalent to 0.001 grams.

milliliter

Symbol: ml

Alternate symbols: mL

A metric unit of volume equivalent to 0.001 liters.

millimeter

Symbol: mm

A metric unit of length equivalent to 0.001 meters.

Ml

Alternate symbols: ML

The symbol for the megaliter, a metric unit of volume equal to 1 000 000 liters.

ml

Alternate symbols: mL

The symbol for the milliliter, a metric unit of volume equal to 0.001 liters.

Mm

The symbol for the megameter, a metric unit of length equal to 1 000 000 meters.

mm

The symbol for the millimeter, a metric unit of length equal to 0.001 meters.