diff --git a/docs/source/index.rst b/docs/source/index.rst
index b33ba8f..e86a21b 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -149,7 +149,8 @@ triggered.
 
 Mails are flagged according to their state, in the ``process_messages`` method:
 
-* ``UNPROCESSED``: MailBot hasn't started looking at this mail
+* unprocessed: MailBot hasn't started looking at this mail, it doesn't have the
+  ``PROCESSING`` nor the ``PROCESSED`` flags
 * ``PROCESSING``: MailBot is checking callbacks, and triggering them if needed
 * ``PROCESSED``: MailBot is done with this mail, and won't process it anymore