PEP 752: Add terminology section (#3918)

* PEP 752: Add terminology section

* fix

peps/pep-0752.rst

@@ -139,6 +139,26 @@ specific scenarios) provides the following benefits:
   feedback would be required because the process to approve a paid organization
   already bestows a certain amount of trust.
 
+Terminology
+===========
+
+The keywords "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
+"RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as
+described in :rfc:`2119`.
+
+Organization
+    `Organizations <orgs_>` are entities that own projects and have various
+    users associated with them. Only organizations have access to the namespace
+    application form.
+Corporate Organization
+    `Corporate organizations <corp-orgs_>` are organizations that have paid for
+    special functionality on PyPI.
+Public Namespace
+    A `public <public-namespaces_>`_ namespace allows for uploads from any
+    project owner.
+Private Namespace
+    A private namespace only allows uploads from an owner of the namespace.
+
 Specification
 =============