diff --git a/source/preprocessor.tex b/source/preprocessor.tex
index 703c5ceac9..109568ad16 100644
--- a/source/preprocessor.tex
+++ b/source/preprocessor.tex
@@ -188,31 +188,31 @@
 \indextext{inclusion!conditional|see{preprocessing directive, conditional inclusion}}
 
 \indextext{\idxcode{defined}}%
-\begin{ncbnf}
+\begin{bnf}
 \nontermdef{defined-macro-expression}\br
     \terminal{defined} identifier\br
     \terminal{defined (} identifier \terminal{)}
-\end{ncbnf}
+\end{bnf}
 
-\begin{ncbnf}
+\begin{bnf}
 \nontermdef{h-preprocessing-token}\br
     \textnormal{any \grammarterm{preprocessing-token} other than \terminal{>}}
-\end{ncbnf}
+\end{bnf}
 
-\begin{ncbnf}
+\begin{bnf}
 \nontermdef{h-pp-tokens}\br
     h-preprocessing-token\br
     h-pp-tokens h-preprocessing-token
-\end{ncbnf}
+\end{bnf}
 
 \indextext{__HAS_INCLUDE@\xname{has_include}}%
-\begin{ncbnf}
+\begin{bnf}
 \nontermdef{has-include-expression}\br
     \terminal{\xname{has_include} ( <} h-char-sequence \terminal{> )}\br
     \terminal{\xname{has_include} ( "} q-char-sequence \terminal{" )}\br
     \terminal{\xname{has_include} (}   string-literal  \terminal{)}\br
     \terminal{\xname{has_include} ( <} h-pp-tokens     \terminal{> )}
-\end{ncbnf}
+\end{bnf}
 
 \pnum
 The expression that controls conditional inclusion