Editing Metric prefix (section)

== Similar symbols and abbreviations ==
In written English, the symbol ''K'' is often used informally to indicate a multiple of thousand in many contexts. For example, one may talk of a ''40K salary'' ({{val|40,000}}), or call the [[Year 2000 problem]] the ''Y2K problem''. In these cases, an uppercase K is often used with an implied unit (although it could then be confused with the symbol for the kelvin temperature unit if the context is unclear). This informal postfix is read or spoken as "thousand", "grand", or just "k".

The financial and general news media mostly use m or M, b or B, and t or T as abbreviations for million, billion (10<sup>9</sup>) and trillion (10<sup>12</sup>), respectively, for large quantities, typically currency<ref>{{Cite news
| agency = Associated Press
| url = https://www.cbc.ca/news/business/obama-unveils-3-8t-budget-proposal-1.1283997
| title = Obama unveils $3.8T budget proposal
| publisher = Canadian Broadcasting Corporation
| date = 13 February 2012
| access-date = 1 March 2012
}}</ref> and population.<ref>{{Cite web
| url = http://www.multichannel.com/article/128853-More_than_65M_Flock_to_Discovery_s_Planet_Earth.php
| title = More than 65M Flock to Discovery's Planet Earth
| publisher = Multichannel.com
| access-date = 1 March 2012
}}</ref>

The [[Medicine|medical]] and [[Automotive industry|automotive]] fields in the United States use the abbreviations ''cc'' or ''ccm'' for cubic centimetres. One&nbsp;[[cubic centimetre]] is equal to one&nbsp;[[millilitre]].

For nearly a century{{Clarify|date=December 2024}}, engineers used the abbreviation ''MCM'' to designate a "thousand [[circular mil]]s" in specifying the cross-sectional area of large [[Electric power transmission|electrical cables]].  Since the mid-1990s, ''[[kcmil]]'' has been adopted as the official designation of a thousand circular mils, but the designation ''MCM'' still remains in wide use. A similar system is used in natural gas sales in the United States: ''m'' (or ''M'') for thousands and ''mm'' (or ''MM'') for millions (thousand thousands) of [[British thermal unit]]s or [[therm]]s, and in the oil industry,<ref name=pesa>{{Cite web
| url = http://www.pesa.com.au/publications/pesa_news/june_july_07/pesanews_8830.html
| title = Purcell, P (2007). ''Disambiguating M''. PESA News 88
| publisher = Pesa.com.au
| access-date = 1 March 2012
| archive-date = 2012-03-25
| archive-url = https://web.archive.org/web/20120325192835/http://www.pesa.com.au/publications/pesa_news/june_july_07/pesanews_8830.html
| url-status = dead
}}</ref> where ''MMbbl'' is the symbol for "millions of barrels". These usages of the capital letter ''M'' for "thousand" in MCM is from [[Roman numerals]], in which ''M'' means 1000.<ref>{{Cite web
| url = https://www.reference.com/home-garden/difference-between-mcm-kcmil-32b016f3e6b497b6
| title = What is the difference between MCM and kcmil?
| date = 4 August 2015
| publisher = Reference.com
| access-date = 5 September 2016
}}</ref><ref name=pesa />