diff --git a/Glossary.md b/Glossary.md
index fef5d2c..aea7bd0 100644
--- a/Glossary.md
+++ b/Glossary.md
@@ -2,4 +2,5 @@ These are the terms which we prefer to use when writing end-user-facing document
 
 - **Account**: A NickServ account on the server.
 - **Connected user**: A user connected to the server, whether they're logged-in to an account or not.
-- **Logged-in**: Logged into a NickServ account.
\ No newline at end of file
+- **Logged-in**: Logged into a NickServ account.
+- **Reserved nickname**: Nickname that only one account can use.
\ No newline at end of file