diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 897522ab2e..ffc40c98ae 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -1979,6 +1979,16 @@ Core layer for images cannot be removed
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-IMAGE_ROOTFS'><glossterm>IMAGE_ROOTFS</glossterm>
+            <glossdef>
+                <para>
+                    The location of the root filesystem.  
+                    This variable is not configurable.  
+                    Do not change it.
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-IMAGE_ROOTFS_EXTRA_SPACE'><glossterm>IMAGE_ROOTFS_EXTRA_SPACE</glossterm>
             <glossdef>
                 <para>