Synopsis:
\definecolor{name}{model}{specification}
Give the name name to the color. For example, after this
\definecolor{silver}{rgb}{0.75,0.75,0.74}
you can use that color name with Hi ho,
\textcolor{silver}{Silver}!.
This example gives the color a more abstract name, so it could change and not be misleading.
\definecolor{logocolor}{RGB}{145,92,131} % RGB needs pdflatex
\newcommand{\logo}{\textcolor{logocolor}{Bob's Big Bagels}}
Often a document’s colors are defined in the preamble, or in the class or style, rather than in the document body.