diff --git a/documentation/poky-ref-manual/ref-variables.xml b/documentation/poky-ref-manual/ref-variables.xml
index 2540a9df01..887c0d0ee8 100644
--- a/documentation/poky-ref-manual/ref-variables.xml
+++ b/documentation/poky-ref-manual/ref-variables.xml
@@ -1726,6 +1726,18 @@
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-TOPDIR'><glossterm>TOPDIR</glossterm>
+            <glossdef>
+                <para>
+                    This variable is the 
+                    <ulink url='http://www.yoctoproject.org/docs/latest/dev-manual/dev-manual.html#yocto-project-build-directory'>
+                    Yocto Project Build Directory</ulink>.
+                    BitBake automatically sets this variable.
+                    The Yocto Project build system uses the build directory when building images. 
+                </para>
+            </glossdef>
+        </glossentry>
+
     </glossdiv>
 
 <!--            <glossdiv id='var-glossary-u'><title>U</title>-->