Kilo-: Difference between revisions

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
imported>Joyous!
Reverted 1 edit by 86.124.187.20 (talk): Rv test
 
imported>Joyous!
Reverted 1 edit by 187.184.11.125 (talk): Rv non-english
 
Line 3: Line 3:
{{Wiktionary|kilo-}}
{{Wiktionary|kilo-}}


'''Kilo''' is a [[decimal prefix|decimal]] [[metric prefix|unit prefix]] in the [[metric system]] denoting multiplication by one [[thousand]] (10<sup>3</sup>). It is used in the [[International System of Units]], where it has the symbol '''k''', in [[Letter case|lowercase]].
'''Kilo''' is a [[unit prefix]] in the [[metric system]] of measurement, denoting multiplication by one [[thousand]] (10<sup>3</sup>). The [[International System of Units]] reserves the [[Letter case|lowercase]] symbol '''k'''.


The prefix ''kilo'' is derived from the [[Greek language|Greek]] word {{lang|el|χίλιοι}} ({{lang|el-Latn|chilioi}}), meaning "thousand".  
''Kilo'' is derived from the [[Greek language|Greek]] word {{lang|el|χίλιοι}} ({{lang|el-Latn|chilioi}}), meaning "thousand".  


In 19th century English it was sometimes spelled chilio, in line with a [[Linguistic purism|puristic]] opinion by [[Thomas Young (scientist)|Thomas Young]].<ref name="Brewster_1832">{{cite book |title=The Edinburgh Encyclopaedia |first=David |last=Brewster |volume=12 |edition=1st American |date=1832 |publisher=Joseph and Edward Parker<!-- |printer=William Brows --> |url=https://books.google.com/books?id=17RGAQAAIAAJ&pg=PA572 |access-date=2015-10-09}}</ref><ref name="Dingler_1823">{{cite book |title=Polytechnisches Journal |first=Johann Gottfried |last=Dingler |volume=11 |date=1823 |publisher=J.W. Gotta'schen Buchhandlung |language=de |location=Stuttgart, Germany |url=https://books.google.com/books?id=wF3zAAAAMAAJ&pg=PA500 |access-date=2015-10-09}}</ref> As an opponent of suggestions to introduce the metric system in Britain, he qualified the nomenclature adopted in France as barbarous.
In 19th century English the prefix was sometimes spelled chilio, in line with a [[Linguistic purism|puristic]] opinion by [[Thomas Young (scientist)|Thomas Young]].<ref name="Brewster_1832">{{cite book |title=The Edinburgh Encyclopaedia |first=David |last=Brewster |volume=12 |edition=1st American |date=1832 |publisher=Joseph and Edward Parker<!-- |printer=William Brows --> |url=https://books.google.com/books?id=17RGAQAAIAAJ&pg=PA572 |access-date=2015-10-09}}</ref><ref name="Dingler_1823">{{cite book |title=Polytechnisches Journal |first=Johann Gottfried |last=Dingler |volume=11 |date=1823 |publisher=J.W. Gotta'schen Buchhandlung |language=de |location=Stuttgart, Germany |url=https://books.google.com/books?id=wF3zAAAAMAAJ&pg=PA500 |access-date=2015-10-09}}</ref> As an opponent of suggestions to introduce the metric system in Britain, he qualified the nomenclature adopted in France as barbarous.


== Examples ==
== Examples ==
Line 23: Line 23:
*one [[kilotonne]] (kt) is 1000 [[Tonne|tonnes]]
*one [[kilotonne]] (kt) is 1000 [[Tonne|tonnes]]


By extension, currencies are also sometimes preceded by the prefix kilo-:
By extension, currencies are sometimes also preceded by the prefix:
* one kiloeuro (k€) is 1000 [[euro]]s
* one kiloeuro (k€) is 1000 [[euro]]s
* one kilodollar (k$) is 1000 [[dollar]]s
* one kilodollar (k$) is 1000 [[dollar]]s


==kilobyte==
==kilobyte==
For the kilobyte, a second definition has been in common use in some fields of [[computer science]] and information technology. It uses ''kilobyte'' to mean 2<sup>10</sup> bytes (= 1024 bytes), because of the [[Mathematical coincidence#Concerning base 2|mathematical coincidence]] that 2<sup>10</sup> is approximately 10<sup>3</sup>. The reason for this application is that digital hardware and architectures natively use [[base 2]] exponentiation, and not [[base 10|decimal]] systems. [[JEDEC memory standards]] still permit this definition, but acknowledge the correct SI usage.
For multiples of the [[byte]] in some fields of [[computer science]] and information technology,  another definition has been in common use, in which the ''kilobyte'' measures 1024 bytes (2<sup>10</sup> bytes), because 2<sup>10</sup> is approximately 10<sup>3</sup>. The reason for this application is that digital hardware natively use [[base 2]] exponentiation.


NIST comments on the confusion caused by these contrasting definitions: "Faced with this reality, the ''IEEE Standards Board'' decided that IEEE standards will use the conventional, internationally adopted, definitions of the SI prefixes", instead of kilo for 1024.<ref>[http://physics.nist.gov/cuu/Units/binary.html Definition of binary prefixes at NIST]</ref>  To address this conflict, a new set of [[binary prefix]]es has been introduced, which is based on powers of 2. Therefore, 1024 bytes are defined as one [[kibibyte]] (1 KiB).
The [[National Institute of Standards and Technology]] (NIST) comments on the confusion caused by these contrasting definitions: "Faced with this reality, the ''IEEE Standards Board'' decided that IEEE standards will use the conventional, internationally adopted, definitions of the SI prefixes."<ref>[http://physics.nist.gov/cuu/Units/binary.html Definition of binary prefixes at NIST]</ref>  A new set of [[binary prefix]]es, based on powers of 2, was introduced by the [[International Electrotechnical Commission]] (IEC), which defines 1024 bytes as one [[kibibyte]] (1 KiB).


==Exponentiation==
==Exponentiation==
When units occur in [[exponentiation]], such as in square and cubic forms, any multiplier prefix is considered part of the unit, and thus included in the exponentiation.
When units occur in [[exponentiation]], such as in square and cubic forms, any multiplier prefix is part of the unit, and thus included in the exponentiation.
* 1&nbsp;km<sup>2</sup> means one square kilometre or the area of a [[Square (geometry)|square]] that measures 1000&nbsp;m on each side or 10<sup>6</sup>&nbsp;m<sup>2</sup> (as opposed to 1000 square meters, which is the area of a square that measures 31.6&nbsp;m on each side).
* 1&nbsp;km<sup>2</sup> means one square kilometre or the area of a [[Square (geometry)|square]] that measures 1000&nbsp;m on each side or 10<sup>6</sup>&nbsp;m<sup>2</sup> (as opposed to 1000 square meters, which is the area of a square that measures 31.6&nbsp;m on each side).
* 1&nbsp;km<sup>3</sup> means one cubic kilometre or the volume of a [[cube]] that measures 1000&nbsp;m on each side or 10<sup>9</sup>&nbsp;m<sup>3</sup> (as opposed to 1000 cubic meters, which is the volume of a cube that measures 10&nbsp;m on each side).
* 1&nbsp;km<sup>3</sup> means one cubic kilometre or the volume of a [[cube]] that measures 1000&nbsp;m on each side or 10<sup>9</sup>&nbsp;m<sup>3</sup> (as opposed to 1000 cubic meters, which is the volume of a cube that measures 10&nbsp;m on each side).


==See also==
==See also==
* [[milli-]] (inverse of kilo- prefix, denoting a factor of 1/1000)
* [[milli-|milli]] (inverse of kilo, denoting a factor of 1/1000)
* [[kibi-]] (binary prefix, denoting a factor of 1024)
* [[kibi-|kibi]] (binary prefix, denoting a factor of 1024)
* [[RKM code]]
* [[RKM code]]



Latest revision as of 01:24, 3 November 2025

Template:Short description Script error: No such module "other uses". Template:Sister project

Kilo is a unit prefix in the metric system of measurement, denoting multiplication by one thousand (103). The International System of Units reserves the lowercase symbol k.

Kilo is derived from the Greek word Script error: No such module "Lang". (Script error: No such module "Lang".), meaning "thousand".

In 19th century English the prefix was sometimes spelled chilio, in line with a puristic opinion by Thomas Young.[1][2] As an opponent of suggestions to introduce the metric system in Britain, he qualified the nomenclature adopted in France as barbarous.

Examples

By extension, currencies are sometimes also preceded by the prefix:

  • one kiloeuro (k€) is 1000 euros
  • one kilodollar (k$) is 1000 dollars

kilobyte

For multiples of the byte in some fields of computer science and information technology, another definition has been in common use, in which the kilobyte measures 1024 bytes (210 bytes), because 210 is approximately 103. The reason for this application is that digital hardware natively use base 2 exponentiation.

The National Institute of Standards and Technology (NIST) comments on the confusion caused by these contrasting definitions: "Faced with this reality, the IEEE Standards Board decided that IEEE standards will use the conventional, internationally adopted, definitions of the SI prefixes."[3] A new set of binary prefixes, based on powers of 2, was introduced by the International Electrotechnical Commission (IEC), which defines 1024 bytes as one kibibyte (1 KiB).

Exponentiation

When units occur in exponentiation, such as in square and cubic forms, any multiplier prefix is part of the unit, and thus included in the exponentiation.

  • 1 km2 means one square kilometre or the area of a square that measures 1000 m on each side or 106 m2 (as opposed to 1000 square meters, which is the area of a square that measures 31.6 m on each side).
  • 1 km3 means one cubic kilometre or the volume of a cube that measures 1000 m on each side or 109 m3 (as opposed to 1000 cubic meters, which is the volume of a cube that measures 10 m on each side).

See also

  • milli (inverse of kilo, denoting a factor of 1/1000)
  • kibi (binary prefix, denoting a factor of 1024)
  • RKM code

References

Template:Reflist

Template:SI prefixes (infobox)

he:תחיליות במערכת היחידות הבינלאומית#קילו

  1. Script error: No such module "citation/CS1".
  2. Script error: No such module "citation/CS1".
  3. Definition of binary prefixes at NIST