diff --git a/book/source/glossary.md b/book/source/glossary.md
index c501965..f48826e 100644
--- a/book/source/glossary.md
+++ b/book/source/glossary.md
@@ -315,6 +315,8 @@ Message Authentication Code
 Meta-Introducer
     An {term}`OpenPGP Certificate` with a {term}`Trust Depth` greater than one.
 
+    A meta-introducer can introduce other (meta-) introducers.
+
 Metadata
     Data related to preferences of an {term}`OpenPGP Certificate` or its {term}`Certificate Holder`, that can be found in {term}`signature` {term}`packets<Packet>`. See [](metadata-in-certificates).