\begin{definition}[Definition:Sign of Number]
The '''sign''' of a number is the symbol indicating whether it is:
: positive, denoted by the symbol $+$
or:
: negative, denoted by the symbol $-$.
Hence a number's '''sign''' has evolved to define the fact of the number being positive or negative independently of the symbol itself.
Thus:
:the '''sign''' of $3.14159$ is positive
and
:the '''sign''' of $-75$ is negative.
\end{definition}