Editing SI base unit (section)

{{Short description|One of the seven units of measurement that define the metric system}}
{{Use dmy dates|date=May 2023}}
[[File:SI base units.svg|thumb|right|266px|
{{Center|The seven SI base units}}
{|
|- 
! {{nowrap|Symbol}} !! Name !! Base quantity
|-
| style="text-align: centre;" | s   || [[second]] || [[time]]
|-
| style="text-align: centre;" | m   || [[metre]] || [[length]]
|-
| style="text-align: centre;" | kg  || {{nowrap|[[kilogram]]}} || [[mass]]
|-
| style="text-align: centre;" | A   || [[ampere]] || [[electric current]]
|-
| style="text-align: centre;" | K   || [[kelvin]] || [[thermodynamic temperature]]
|-
| style="text-align: centre;" | mol || [[mole (unit)|mole]] || [[amount of substance]]
|-
| style="text-align: centre;" | cd  || [[candela]] || [[luminous intensity]]
|-
|}
]]

The '''SI base units''' are the standard [[units of measurement]] defined by the [[International System of Units]] (SI) for the seven [[base quantities]] of what is now known as the [[International System of Quantities]]: they are notably a basic set from which all other [[SI units]] can be [[SI derived unit|derived]]. The units and their physical quantities are the [[second]] for [[time]], the [[metre]] (sometimes spelled meter) for [[length]] or [[distance]], the [[kilogram]] for [[mass]], the [[ampere]] for [[electric current]], the [[kelvin]] for [[thermodynamic temperature]], the [[Mole (unit)|mole]] for [[amount of substance]], and the [[candela]] for [[luminous intensity]]. The SI base units are a fundamental part of modern [[metrology]], and thus part of the foundation of modern science and technology.

The SI base units form a set of mutually independent dimensions as required by [[dimensional analysis]] commonly employed in science and technology.{{citation needed|date=January 2020}}

The names and symbols of SI base units are written in lowercase, except the symbols of those named after a person, which are written with an initial capital letter.  For example, the ''metre'' has the symbol m, but the ''[[kelvin]]'' has symbol K, because it is named after [[William Thomson, 1st Baron Kelvin|Lord Kelvin]] and the ''[[ampere]]'' with symbol A is named after [[André-Marie Ampère]].