diff --git a/Doc/ref/ref3.tex b/Doc/ref/ref3.tex
index d3faa1fb461..d5711d2fde6 100644
--- a/Doc/ref/ref3.tex
+++ b/Doc/ref/ref3.tex
@@ -380,7 +380,7 @@ comparison: if two numbers compare equal (e.g., \code{1} and
 \code{1.0}) then they can be used interchangeably to index the same
 dictionary entry.
 
-Dictionaries are \obindex{mutable}mutable; they are created by the
+Dictionaries are mutable; they are created by the
 \code{\{...\}} notation (see section \ref{dict}, ``Dictionary
 Displays'').