Wiktionary
n. (context mathematics English) The character used to separate the integer and fractional part of a number in a digital representation of a number, regardless of the base used.
Wikipedia
In mathematics and computing, a radix point (or radix character) is the symbol used in numerical representations to separate the integer part of a number (to the left of the radix point) from its fractional part (to the right of the radix point). "Radix point" is a general term that applies to all number bases. In base 10 notation, the radix point is more commonly called the decimal point, where the prefix deci- implies base 10. Similarly, the term "binary point" is used for base 2.
In English-speaking countries, the radix point is usually a small dot (.) placed either on the baseline or halfway between the baseline and the top of the numerals. In many other countries, the radix point is a comma (,) placed on the baseline. It is important to know which notation is being used when working in different software programs.