diff --git a/chapters/operatorsandexpressions.tex b/chapters/operatorsandexpressions.tex
index 373d02d3a..31c0f2bb7 100644
--- a/chapters/operatorsandexpressions.tex
+++ b/chapters/operatorsandexpressions.tex
@@ -361,6 +361,7 @@ \subsection{Built-in Variable time}\label{built-in-variable-time}\indexinline{ti
 
 All declared variables are functions of the independent variable \lstinline!time!.
 The variable \lstinline!time! is a built-in variable available in all models and blocks, which is treated as an input variable.
+The name \lstinline!time! is reserved and may not declared in any class.
 It is implicitly defined as:
 \begin{lstlisting}[language=modelica]
 input Real time (final quantity = "Time",