Fix case for 'Unix'
diff --git a/Doc/lib/tkinter.tex b/Doc/lib/tkinter.tex
index 405f041..0cc8d58 100644
--- a/Doc/lib/tkinter.tex
+++ b/Doc/lib/tkinter.tex
@@ -319,7 +319,7 @@
\item[\var{options} ]
configure the widget's appearance and in some cases, its
behavior. The options come in the form of a list of flags and values.
-Flags are proceeded by a `-', like unix shell command flags, and
+Flags are proceeded by a `-', like Unix shell command flags, and
values are put in quotes if they are more than one word.
\end{description}