Metre

  • metre
    metric seal.svg
    seal of the international bureau of weights and measures (bipm) – use measure (greek: ΜΕΤΡΩ ΧΡΩ)
    general information
    unit systemsi base unit
    unit oflength
    symbolm 
    conversions
    1 m in ...... is equal to ...
       si units   1000 mm
    0.001 km
       imperial/us units   ≈ 1.0936 yd
     ≈ 3.2808 ft
     ≈ 39.370 in
       nautical units   ≈ 0.00053996 nmi

    the metre (commonwealth spelling and bipm spelling[1]) or meter (american spelling[2]) (from the french unit mètre, from the greek noun μέτρον, "measure") is the base unit of length in the international system of units (si). the si unit symbol is m.[3] the metre is defined as the length of the path travelled by light in a vacuum in 1/299 792 458 of a second.[1] the metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the north pole along a great circle, so the earth's circumference is approximately 40000 km. in 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). in 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. in 1983, the current definition was adopted.

  • spelling
  • etymology
  • history of definition
  • si prefixed forms of metre
  • equivalents in other units
  • see also
  • notes
  • references

Metre
Metric seal.svg
Seal of the International Bureau of Weights and Measures (BIPM) – Use measure (Greek: ΜΕΤΡΩ ΧΡΩ)
General information
Unit systemSI base unit
Unit oflength
Symbolm 
Conversions
1 m in ...... is equal to ...
   SI units   1000 mm
0.001 km
   Imperial/US units   ≈ 1.0936 yd
 ≈ 3.2808 ft
 ≈ 39.370 in
   Nautical units   ≈ 0.00053996 nmi

The metre (Commonwealth spelling and BIPM spelling[1]) or meter (American spelling[2]) (from the French unit mètre, from the Greek noun μέτρον, "measure") is the base unit of length in the International System of Units (SI). The SI unit symbol is m.[3] The metre is defined as the length of the path travelled by light in a vacuum in 1/299 792 458 of a second.[1] The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately 40000 km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. In 1983, the current definition was adopted.