diff --git a/doc/arm/Bv9ARM-book.xml b/doc/arm/Bv9ARM-book.xml
index 1766c83bc3..9a5467bc0e 100644
--- a/doc/arm/Bv9ARM-book.xml
+++ b/doc/arm/Bv9ARM-book.xml
@@ -10665,7 +10665,7 @@ example.com                 CNAME   rpz-tcp-only.
 	  </para>
 	  <para>
 	    With both methods when named gets a NXDOMAIN response
-	    it examines a seperate namespace to see if the NXDOMAIN
+	    it examines a separate namespace to see if the NXDOMAIN
 	    response should be replaced with an alternative response.
 	  </para>
 	  <para>