diff --git a/doc/configuration-file.xml b/doc/configuration-file.xml
index e2e519b2..9bb4795e 100644
--- a/doc/configuration-file.xml
+++ b/doc/configuration-file.xml
@@ -262,7 +262,7 @@ conninfo='host=node1 user=repmgr dbname=repmgr connect_timeout=2'</programlistin
 
     <indexterm>
       <primary>repmgr.conf</primary>
-      <secondary>ostgreSQL major version upgrades</secondary>
+      <secondary>PostgreSQL major version upgrades</secondary>
     </indexterm>
 
     <para>