diff --git a/doc/src/sgml/pgbuffercache.sgml b/doc/src/sgml/pgbuffercache.sgml
index eeb85a0e049..99ad2e68785 100644
--- a/doc/src/sgml/pgbuffercache.sgml
+++ b/doc/src/sgml/pgbuffercache.sgml
@@ -278,7 +278,7 @@
        <structfield>os_page_num</structfield> <type>bigint</type>
       </para>
       <para>
-       number of OS memory page for this buffer
+       Number of OS memory page for this buffer
       </para></entry>
      </row>