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Centimetre
Centimetre  

File:CarpentersRule.png a carpenters' ruler with centimetre divisions  
Unit information  
Unit system  SI and CGS 
Unit of  length 
Symbol  cm 
Unit conversions  
1 cm in ...  ... is equal to ... 
SI  10 mm 
imperial & US system  ~0.3937 in 
40x40px  Look up centimetre in Wiktionary, the free dictionary. 
A centimetre (international spelling as used by the International Bureau of Weights and Measures; symbol cm) or centimeter (American spelling) is a unit of length in the metric system, equal to one hundredth of a metre, centi being the SI prefix for a factor of ^{1}⁄_{100}.^{[1]} The centimetre was the base unit of length in the now deprecated centimetregramsecond (CGS) system of units.
Though for many physical quantities, SI prefixes for factors of 10^{3}—like milli and kilo—are often preferred by technicians, the centimetre remains a practical unit of length for many everyday measurements. A centimetre is approximately the width of the fingernail of an average adult person.
Contents
Equivalence to other units of length
1 centimetre = 10 millimetres = 0.01 metres = 0.393700787401574803149606299212598425196850 inches
One cubic centimetre is equal to 1 millilitre, under the current SI system of units.
Uses of centimetre
In addition to its use in the measurement of length, the centimetre is used:
 sometimes, to report the level of rainfall as measured by a rain gauge ^{[2]}
 in the CGS system, the centimetre is used to measure capacitance, where 1 cm of capacitance = 1.113×10^{−12} farads^{[3]}
 in maps, centimetres are used to make conversions from map scale to real world scale (kilometres)
 to represent second moment of areas (cm^{4})
 as the inverse of the kayser, a CGS unit, and thus a nonSI metric unit of wavenumber: 1 kayser = 1 wave per centimetre; or, more generally, (wavenumber in kaysers) = 1/(wavelength in centimetres). The SI unit of wavenumber is the inverse metre, m^{−1}.
Unicode symbols
For the purposes of compatibility with Chinese, Japanese and Korean (CJK) characters, Unicode has symbols for:^{[4]}
 centimetre (㎝) – code 339D
 square centimetre (㎠) – code 33A0
 cubic centimetre (㎤) – code 33A4
They are mostly used only with East Asian fixedwidth CJK fonts, because they are equal in size to one Chinese character.
See also
 1 E2 m
 Conversion of units, for comparison with other units of length
 Reciprocal centimetre
 Orders of magnitude (length)
References
 ^ BIPM  SI prefixes
 ^ Rain Measurement, Rain Gauge, Wireless Rain Gauge, Rain Gage, Rain Gauge Data
 ^ Capacitance  from Eric Weisstein's World of Physics
 ^ [1] CJK Compatibility excerpt from The Unicode Standard, Version 4.1.
 CJK Compatibility excerpt from The Unicode Standard, Version 4.4 and coexterior users.
