Updated from openstack-manuals

Change-Id: Ic29980b801bb5bd9d528f3879adef1cf82046313

doc/glossary/glossary-terms.xml

@@ -2178,20 +2178,17 @@
     </glossentry>
 
     <glossentry>
-      <glossterm>core project</glossterm>
+      <glossterm>core service</glossterm>
       <indexterm class="singular">
-          <primary>core project</primary>
+          <primary>core service</primary>
         </indexterm>
 
       <glossdef>
-        <para>An official OpenStack project. Currently consists of Compute
-        (nova), Object Storage (swift), Image service (glance), Identity
-        (keystone), Dashboard (horizon), Networking (neutron), and Block
-        Storage (cinder), Telemetry (ceilometer), Orchestration (heat),
-        Database service (trove), Bare Metal service (ironic),
-        Data processing service (sahara). However, this
-        definition is changing based on
-        community discussions about the "Big Tent".
+        <para>An official OpenStack service defined as core by
+        DefCore Committee. Currently, consists of
+        Block Storage service (cinder), Compute service (nova),
+        Identity service (keystone), Image service (glance),
+        Networking service (neutron), and Object Storage service (swift).
         </para>
       </glossdef>
     </glossentry>
@@ -6453,6 +6450,22 @@
       </glossdef>
     </glossentry>
 
+    <glossentry>
+      <glossterm>optional service</glossterm>
+      <indexterm class="singular">
+          <primary>optional service</primary>
+        </indexterm>
+
+      <glossdef>
+        <para>An official OpenStack service defined as optional by
+        DefCore Committee. Currently, consists of
+        Dashboard (horizon), Telemetry service (Telemetry),
+        Orchestration service (heat), Database service (trove),
+        Bare Metal service (ironic), and so on.
+        </para>
+      </glossdef>
+    </glossentry>
+
     <glossentry>
       <glossterm>Orchestration</glossterm>
       <indexterm class="singular">