diff --git a/source/declarations.tex b/source/declarations.tex
index 2e575bbbba..c08374fbad 100644
--- a/source/declarations.tex
+++ b/source/declarations.tex
@@ -9598,9 +9598,10 @@
 
 \pnum
 \recommended
-Implementations should use the \tcode{deprecated} attribute to produce a diagnostic
-message in case the program refers to a name or entity other than to declare it, after a
-declaration that specifies the attribute. The diagnostic message should include the text provided
+Implementations should use the \tcode{deprecated} attribute to produce a warning
+in case the program refers to a name or entity other than to declare it, after a
+declaration that specifies the attribute.
+The warning should include the text provided
 within the \grammarterm{attribute-argument-clause} of any \tcode{deprecated} attribute applied
 to the name or entity.
 The value of
diff --git a/source/intro.tex b/source/intro.tex
index 75705a2bab..62f7259047 100644
--- a/source/intro.tex
+++ b/source/intro.tex
@@ -694,6 +694,18 @@
 \tcode{false}.
 \end{example}
 
+\indexdefn{warning}%
+\definition{warning}{defns.warning}
+message belonging to a subset of
+\termref{defns.diagnostic}{diagnostic message}{s}
+produced to provide the user with information about the program,
+not as a consequence of a \Cpp{} program being rejected
+
+\begin{example}
+The \tcode{#warning} directive produces a warning.
+The \tcode{#error} directive produces a diagnostic message that is not a warning\iref{cpp.error}.
+\end{example}
+
 \indexdefn{program!well-formed}%
 \definition{well-formed program}{defns.well.formed}
 \Cpp{} program constructed according to the syntax and semantic rules
diff --git a/source/preprocessor.tex b/source/preprocessor.tex
index ee7959abeb..8b91f30abc 100644
--- a/source/preprocessor.tex
+++ b/source/preprocessor.tex
@@ -2098,7 +2098,7 @@
 \begin{ncsimplebnf}
 \terminal{\# warning} \opt{pp-tokens} new-line
 \end{ncsimplebnf}
-requires the implementation to produce at least one diagnostic message
+requires the implementation to produce at least one warning
 for the preprocessing translation unit\iref{intro.compliance.general}.
 \recommended
 Any diagnostic message caused by either of these directives