diff --git a/source/expressions.tex b/source/expressions.tex
index fb3c8c03bb..4f1bf63c63 100644
--- a/source/expressions.tex
+++ b/source/expressions.tex
@@ -2079,7 +2079,7 @@
 \end{bnf}
 
 \pnum
-The \grammarterm{id-expression} $P$ in a \grammarterm{pack-index-expression}
+The \grammarterm{id-expression} $P$ of a \grammarterm{pack-index-expression}
 shall be an \grammarterm{identifier} that denotes a pack.
 
 \pnum