\begin{definition}[Definition:Decimal Expansion/Decimal Point]
Let $x \in \R$ have a decimal expansion:
:$n. d_1 d_2 d_3 \ldots$
The dot that separates the integer part from the fractional part of $x$ is called the '''decimal point'''.
That is, it is the radix point when used specifically for a base $10$ representation.
\end{definition}