diff --git a/book/source/04-certificates.md b/book/source/04-certificates.md
index 30f81b9..db334e6 100644
--- a/book/source/04-certificates.md
+++ b/book/source/04-certificates.md
@@ -193,7 +193,7 @@ Key attributes, such as capabilities (like *signing* or *encryption*) and expira
 
 - **Subkey metadata** is defined within the [subkey binding signature](binding_subkeys) that links the subkey to the certificate.
 
-- **User ID metadata** is is associated via the [certifying self-signature](bind_ident) that links the identity to the certificate.
+- **Identity component metadata** is associated via the [certifying self-signature](bind_ident) that links the identity (usually in the form of a User ID) to the certificate.
 
 It is crucial to note that the components of an OpenPGP certificate remain static after their creation. The use of signatures to store metadata allows for subsequent modifications without altering the original components. For instance, a certificate holder can update the expiration time of a component by issuing a new, superseding signature.