diff --git a/doc/glossary.rst b/doc/glossary.rst
index 893927de67c..d3a0dd8f4cb 100644
--- a/doc/glossary.rst
+++ b/doc/glossary.rst
@@ -324,6 +324,12 @@
 	Node
                 See :term:`Ceph Node`.
 
+	Object Storage
+                Object storage is one of three kinds of storage relevant to
+                Ceph. The other two kinds of storage relevant to Ceph are file
+                storage and block storage. Object storage is the category of
+                storage most fundamental to Ceph.
+
 	Object Storage Device
                 See :term:`OSD`.