diff --git a/book/source/glossary.md b/book/source/glossary.md
index 304fd70..e8ba2b5 100644
--- a/book/source/glossary.md
+++ b/book/source/glossary.md
@@ -69,7 +69,7 @@ Certificate Authority
     See {term}`Certification Authority`
 
 Certificate Holder
-    A person or other entity, that holds an {term}`Transferable Secret Key` and thus is able to modify the accompanying {term}`OpenPGP Certificate`.
+    A person or other entity, that holds an {term}`Transferable Secret Key` and thus is able to modify the accompanying {term}`OpenPGP Certificate`. Typically this is the owner of {term}`OpenPGP key`.
 
 Certification
     A certification, in OpenPGP, is a signature that makes a statement about an {term}`identity` in a {term}`certificate<OpenPGP Certificate>`, or an entire {term}`certificate<OpenPGP Certificate>`.