Editing Decimal separator (section)

{{Short description|Numerical symbol}}
{{Use dmy dates|date=November 2022}}
{{Redirect|Decimal period|the period of a repeating decimal fraction|Repeating decimal}}
{{Numeral systems}}

[[FIle:Decimal separators.svg|thumb|alt=Four types of separating decimals: a) 1,234.56. b) 1.234,56. c) 1'234,56. d) ١٬٢٣٤٫٥٦.|Both a [[comma]] and a [[full stop]] (or period) are generally accepted decimal separators for international use. The [[apostrophe]] and Arabic decimal separator are also used in certain contexts.]]
[[File:Thousands separators.gif|thumb|Three ways to group the number ten thousand with digit group separators: {{blist
  | [[Space (punctuation)|Space]], the internationally recommended thousands separator.
  | [[Full stop]] (or period), the thousands separator used in many non-English speaking countries.
  | [[Comma]], the thousands separator used in most English-speaking countries.
}}]]

A '''decimal separator''' is a symbol that separates the [[integer]] part from the [[fractional part]] of a [[number]] written in [[decimal]] form. Different countries officially designate different symbols for use as the separator. The choice of symbol can also affect the choice of symbol for the [[#Digit grouping|thousands separator]] used in digit grouping.

Any such symbol can be called a '''decimal mark''', '''decimal marker''', or '''decimal sign'''. Symbol-specific names are also used; '''decimal point''' and '''decimal comma''' refer to a dot (either [[Baseline dot|baseline]] or [[Middle dot|middle]]) and [[comma]] respectively, when it is used as a decimal separator; these are the usual terms used in English,<ref>{{cite web|url=https://www.collinsdictionary.com/dictionary/english/decimal-point|title=Decimal point definition and meaning {{!}} Collins English Dictionary|website=www.collinsdictionary.com|language=en|access-date=2018-07-05}}</ref><ref name=":0">{{Cite web|last=Weisstein|first=Eric W.|title=Decimal Point|url=https://mathworld.wolfram.com/DecimalPoint.html|access-date=2020-08-22|website=mathworld.wolfram.com|language=en}}</ref><ref>{{cite web|url=https://dictionary.cambridge.org/dictionary/english/decimal-point|title=decimal point Meaning in the Cambridge English Dictionary|website=dictionary.cambridge.org|language=en|access-date=2018-07-05}}</ref> with the aforementioned generic terms reserved for abstract usage.<ref>{{Cite news|url=https://www.howtogeek.com/245510/how-to-change-excels-decimal-separators-from-periods-to-commas/|title=How to Change Excel's Decimal Separators from Periods to Commas|access-date=2018-07-05|language=en-US}}</ref><ref>{{Cite news|url=https://www.smartickmethod.com/blog/math/learning-resources/decimal-separators/|title=Decimal Separators: Points or commas? - Elementary Math|date=2018-01-19|work=Elementary Math|access-date=2018-07-05|language=en}}</ref>

In many contexts, when a number is spoken, the function of the separator is assumed by the spoken name of the symbol: ''comma'' or ''point'' in most cases.<ref>{{Cite web|title=Definition of Decimal Point|url=https://www.mathsisfun.com/definitions/decimal-point.html|access-date=2020-08-22|website=www.mathsisfun.com}}</ref><ref name=":0" /><ref>{{Cite news|url=https://www.grammarphobia.com/blog/2012/02/decimal-point.html|title=Mythematics: a decimal point|date=2012-02-17|work=Grammarphobia|access-date=2018-07-05|language=en-US}}</ref> In some specialized contexts, the word ''decimal'' is instead used for this purpose (such as in [[International Civil Aviation Organization]]-regulated [[air traffic control]] communications). In mathematics, the decimal separator is a type of [[#Radix point|radix point]], a term that also applies to number systems with bases other than ten.