diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 235939c6c7..4a7efdbeab 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -4028,6 +4028,19 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-INITRD_IMAGE'><glossterm>INITRD_IMAGE</glossterm>
+            <glossdef>
+                <para>
+                    When building a "live" bootable image (i.e. when
+                    <link linkend='var-IMAGE_FSTYPES'><filename>IMAGE_FSTYPES</filename></link>
+                    contains "live"), <filename>INITRD_IMAGE</filename>
+                    specifies the image recipe that should be built
+                    to provide the initial RAM disk image.
+                    The default value is "core-image-minimal-initramfs".
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-INITSCRIPT_NAME'><glossterm>INITSCRIPT_NAME</glossterm>
             <glossdef>
                 <para>