AskDefine | Define meter

Dictionary Definition



1 the basic unit of length adopted under the Systeme International d'Unites (approximately 1.094 yards) [syn: metre, m]
2 any of various measuring instruments for measuring a quantity
3 (prosody) the accent in a metrical foot of verse [syn: metre, measure, beat, cadence]
4 rhythm as given by division into parts of equal time [syn: metre, time]


1 measure with a meter; "meter the flow of water"
2 stamp with a meter indicating the postage; "meter the mail"

User Contributed Dictionary


Alternative spellings

  • metre (for senses 3 to 5)


From mètre, originally from μέτρον (metron) "a measure".


  • /ˈmiːtə(ɻ)/


  1. (always meter) A device that measures things.
  2. A parking meter.
  3. mostly US (elsewhere metre) The base unit of length in the International System of Units (SI), equal to the distance light will travel in a vacuum in 1/299792458 second.
  4. : an increment of music; the overall rhythm; particularly, the number of beats in a measure.
  5. In the context of "Prosody": : The rhythm pattern in a poem.
counter, measuring instrument
unit of measure, 100 cm
  • Arabic: (mitr)
  • Chinese: (mǐ)
  • Czech: metr
  • Dutch: meter
  • Estonian: meeter
  • Finnish: metri
  • French: mètre
  • German: Meter
  • Greek: μέτρο (métro)
  • Hebrew: מטר (meter)
  • Hungarian: méter
  • Icelandic: metri
  • Interlingua: metro
  • Italian: metro
  • Japanese: メートル, (mētoru)
  • Korean: 미터 (miteo)
  • Norwegian: meter
  • Polish: metr
  • Portuguese: metro
  • Romanian: metru
  • Russian: метр
  • Slovak: meter
  • Spanish: metro
  • Swedish: meter
  • Tatar: meter
  • Turkish: metre
  • Vietnamese: mét
  • Yiddish: מעטער (meter)
increment of music
rhythym of poetry


  1. To measure with a metering device.



  • /ˈmetər/

Etymology 1


  1. meter (a distance of 100 centimeters. The base unit of the metric system).
  2. meter (a device that measures things).

Etymology 2


  1. godmother



Latin mittere


  1. to put


pt-conj-er met



mittere, present infinitive of mitto.


  1. to put, to insert


es-conj-er met




  1. a metre; the SI-unit
  2. Rhythm or measure in verse
  3. a meter; a device that measures things.

Usage notes

Indefinite form plural could also be metrar/metrars



Extensive Definition

This article is about the unit of length. For other uses of metre or meter, see meter (disambiguation).
The metre or meter is a measure of length. It is the basic unit of length in the metric system and in the International System of Units (SI), used around the world for general and scientific purposes. 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 represent of the distance from the equator to the north pole through Paris. Today, it is defined by the International Bureau of Weights and Measures as the distance travelled by light in absolute vacuum in of a second.
The symbol for metre is m (never capital M). Decimal multiples and submultiples of the metre, such as kilometre (1000 metres) and centimetre ( metre), are indicated by adding SI prefixes to metre (see table below).


The word metre is from the Greek metron (), "a measure" via the French mètre. Its first recorded usage in English meaning this unit of length is from 1797.

Meridional definition

In the eighteenth century, there were two favoured approaches to the definition of the standard unit of length. One approach suggested defining the metre as the length of a pendulum with a half-period of one second. The other approach suggested defining the metre as one ten-millionth of the length of the Earth's meridian along a quadrant, that is the distance from the equator to the north pole. In 1791, the French Academy of Sciences selected the meridional definition over the pendular definition because the force of gravity varies slightly over the surface of the Earth, which affects the period of a pendulum.
In order to establish a universally accepted foundation for the definition of the metre, measurements of this meridian more accurate than those available at that time were imperative. The Bureau des Longitudes commissioned an expedition led by Delambre and Pierre Méchain, lasting from 1792 to 1799, which measured the length of the meridian between Dunkerque and Barcelona. This portion of the meridian, which also passes through Paris, was to serve as the basis for the length of the half meridian, connecting the North Pole with the Equator.
However, in 1793, France adopted as its official unit of length a metre based on provisional results from the expedition as its official unit of length. Although it was later determined that the first prototype metre bar was short by a fifth of a millimetre due to miscalculation of the flattening of the Earth, this length became the standard. The circumference of the Earth through the poles is therefore slightly more than forty million metres.

Prototype metre bar

In the 1870s and in light of modern precision, a series of international conferences were held to devise new metric standards. The Metre Convention (Convention du Mètre) of 1875 mandated the establishment of a permanent International Bureau of Weights and Measures (BIPM: Bureau International des Poids et Mesures) to be located in Sèvres, France. This new organisation would preserve the new prototype metre and kilogram standards when constructed, distribute national metric prototypes, and maintain comparisons between them and non-metric measurement standards. The organization created a new prototype bar in 1889 at the first General Conference on Weights and Measures (CGPM: Conférence Générale des Poids et Mesures), establishing the International Prototype Metre as the distance between two lines on a standard bar composed of an alloy of ninety percent platinum and ten percent iridium, measured at the melting point of ice.

Standard wavelength of krypton-86 emission

In 1893, the standard metre was first measured with an interferometer by Albert A. Michelson, the inventor of the device and an advocate of using some particular wavelength of light as a standard of distance. By 1925, interferometry was in regular use at the BIPM. However, the International Prototype Metre remained the standard until 1960, when the eleventh CGPM defined the metre in the new SI system as equal to 1,650,763.73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum. The original international prototype of the metre is still kept at the BIPM under the conditions specified in 1889.

Standard wavelength of helium-neon laser light

To further reduce uncertainty, the seventeenth CGPM in 1983 replaced the definition of the metre with its current definition, thus fixing the length of the metre in terms of time and the speed of light:
The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.
Note that this definition had the effect of fixing the speed of light in a vacuum at precisely 299,792,458 metres per second. Although the metre is now defined in terms of time-of-flight, actual laboratory realisations of the metre are still delineated by counting the required number of wavelengths of light along the distance. An intended byproduct of the 17th CGPM’s definition was that it enabled scientists to measure the wavelength of their lasers with one-fifth the uncertainty. To further facilitate reproducibility from lab to lab, the 17th CGPM also made the iodine-stabilised helium-neon laser “a recommended radiation” for realising the metre. For purposes of delineating the metre, the BIPM currently considers the HeNe laser wavelength to be as follows: λHeNe = 632.99139822 nm with an estimated relative standard uncertainty (U) of 2.5 × 10–11. This uncertainty is currently the limiting factor in laboratory realisations of the metre as it is several orders of magnitude poorer than that of the second (U = 5 × 10–16). Consequently, a practical realisation of the metre is usually delineated (not defined) today in labs as 1,579,800.298728(39) wavelengths of helium-neon laser light in a vacuum.

Timeline of definition

  • 1791 March 30 — The French National Assembly accepts the proposal by the French Academy of Sciences that the new definition for the metre be equal to one ten-millionth of the length of the Earth's meridian along a quadrant through Paris, that is the distance from the equator to the north pole.
  • 1795 — Provisional metre bar constructed of brass.
  • 1799 December 10 — The French National Assembly specifies the platinum metre bar, constructed on 23 June 1799 and deposited in the National Archives, as the final standard.
  • 1927 October 6 — The seventh CGPM adjusts the definition of the length to be the distance, at 0 °C, between the axes of the two central lines marked on the prototype bar of platinum-iridium, this bar being subject to one standard atmosphere of pressure and supported on two cylinders of at least one centimetre diameter, symmetrically placed in the same horizontal plane at a distance of 571 millimetres from each other.
  • 1960 October 20 — The eleventh CGPM defines the length to be equal to 1,650,763.73 wavelengths in vacuum of the radiation corresponding to the transition between the 2p10 and 5d5 quantum levels of the krypton-86 atom.
  • 1983 October 21 — The seventeenth CGPM defines the length as equal to the distance travelled by light in vacuum during a time interval of of a second.

SI prefixed forms of metre

SI prefixes are often employed to denote decimal multiples and submultiples of the metre, as shown in the table below.

Equivalents in other units

Within this table, "inch" means "international inch".

See also



meter in Afrikaans: Meter
meter in Tosk Albanian: Meter
meter in Arabic: متر
meter in Asturian: Metru
meter in Bengali: মিটার
meter in Min Nan: Kong-chhioh
meter in Belarusian: Метр
meter in Belarusian (Tarashkevitsa): Мэтар
meter in Bosnian: Metar
meter in Breton: Metr
meter in Bulgarian: Метър
meter in Catalan: Metre
meter in Czech: Metr
meter in Welsh: Metr
meter in Danish: Meter
meter in German: Meter
meter in Dhivehi: މީޓަރު
meter in Estonian: Meeter
meter in Modern Greek (1453-): Μέτρο (μονάδα μήκους)
meter in Spanish: Metro
meter in Esperanto: Metro
meter in Basque: Metro
meter in Persian: متر
meter in French: Mètre
meter in Friulian: Metri
meter in Irish: Méadar
meter in Gan Chinese: 米
meter in Galician: Metro
meter in Korean: 미터
meter in Croatian: Metar
meter in Bishnupriya: মিটার
meter in Indonesian: Meter
meter in Interlingua (International Auxiliary Language Association): Metro
meter in Icelandic: Metri
meter in Italian: Metro
meter in Hebrew: מטר
meter in Javanese: Meter
meter in Kannada: ಮೀಟರ್
meter in Georgian: მეტრი
meter in Kazakh: Метр
meter in Swahili (macrolanguage): Mita
meter in Kurdish: Mitir
meter in Lao: ແມັດ
meter in Latin: Metrum
meter in Latvian: Metrs
meter in Luxembourgish: Meter
meter in Lithuanian: Metras
meter in Hungarian: Méter
meter in Macedonian: Метар
meter in Maltese: Metru
meter in Marathi: मीटर
meter in Malay (macrolanguage): Meter
meter in Mongolian: Метр
meter in Dutch: Meter
meter in Japanese: メートル
meter in Norwegian: Meter
meter in Norwegian Nynorsk: Meter
meter in Narom: Mète
meter in Occitan (post 1500): Mètre
meter in Low German: Meter
meter in Polish: Metr
meter in Portuguese: Metro
meter in Kölsch: Läng
meter in Romanian: Metru
meter in Quechua: Mitru
meter in Russian: Метр
meter in Scots: Metre
meter in Albanian: Metri
meter in Simple English: Metre
meter in Silesian: Meter
meter in Church Slavic: Метро
meter in Slovenian: Meter
meter in Serbian: Метар
meter in Serbo-Croatian: Metar
meter in Sundanese: Méter
meter in Finnish: Metri
meter in Swedish: Meter
meter in Tagalog: Metro
meter in Tamil: மீட்டர்
meter in Telugu: మీటరు
meter in Thai: เมตร
meter in Vietnamese: Mét
meter in Tajik: Метр
meter in Turkish: Metre
meter in Ukrainian: Метр
meter in Urdu: میٹر (پیمائش)
meter in Venetian: Metro
meter in Vlaams: Meter (lengtemoate)
meter in Yiddish: מעטער
meter in Contenese: 米
meter in Samogitian: Metros
meter in Chinese: 米 (单位)
meter in Slovak: Meter

Synonyms, Antonyms and Related Words

Alexandrine, Stabreim, VOM, VTVM, accent, accentuation, alliterative meter, alternation, ammeter, ampere-hour meter, amphibrach, amphimacer, anacrusis, anapest, antispast, appraise, appraiser, appreciate, arsis, assay, assayer, assess, assessor, bacchius, beat, cadence, cadency, caesura, calculate, calibrate, caliper, cartographer, catalexis, check a parameter, chloriamb, chloriambus, chorographer, colon, compute, coulometer, count-rate meter, counterpoint, cretic, cyclicalness, dactyl, dactylic hexameter, diaeresis, dial, dimeter, dipody, divide, dochmiac, duodial, dynamometer, elegiac, elegiac couplet, elegiac pentameter, emphasis, epitrite, estimate, estimator, evaluate, evaluator, expansion ammeter, faradmeter, fathom, feminine caesura, foot, galvanometer, gauge, gauger, geodesist, graduate, heptameter, heptapody, heroic couplet, hexameter, hexapody, hysteresis meter, iamb, iambic, iambic pentameter, ictus, illuminometer, instrument, interferometer, intermittence, intermittency, ionic, ionization gauge, jingle, land surveyor, lilt, magnetometer, masculine caesura, measure, measurer, megohmmeter, mensurate, mete, metrical accent, metrical foot, metrical group, metrical pattern, metrical unit, metrics, metron, mhometer, milliammeter, molossus, mora, movement, moving-coil meter, number, numbers, oceanographer, ohmmeter, oscillation, pH meter, pace, paeon, pendulum motion, pentameter, pentapody, period, periodicalness, periodicity, piston motion, plumb, potentiometer, prize, probe, proceleusmatic, prosodic pattern, prosody, pulsation, pyrrhic, quantify, quantitative meter, quantity, quantize, rate, reappearance, recurrence, regular wave motion, reoccurrence, return, rhyme, rhythm, rhythmic pattern, scanning, scansion, seasonality, size, size up, sound, span, spondee, sprung rhythm, step, stress, survey, surveyor, swing, syllabic meter, syzygy, take a reading, telemeter, tetrameter, tetrapody, tetraseme, thermoammeter, thermocouple, thermoelectrometer, thesis, time-interval meter, topographer, triangulate, tribrach, trimeter, tripody, triseme, trochee, undulation, valuate, valuator, value, valuer, variometer, vers libre, versification, voltameter, voltmeter, weigh
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