diff --git a/index.bs b/index.bs
index 8ff6b47..321d63e 100644
--- a/index.bs
+++ b/index.bs
@@ -34,15 +34,20 @@ This document is intended for:
 
 # What is a web user agent # {#what}
 
+A <dfn lt="general user agent">user agent</dfn>, in general, is any software entity
+that interacts with other entities on behalf of its user.
+User agents include many operating systems; email clients; PDF, ebook, and image viewers;
+[=credential managers=], including digital wallets; and many other kinds of software.
+
 <!-- TODO: Export this once it can replace the Infra definition. -->
 A <dfn lt="user agent|web user agent" noexport>web user agent</dfn> is
 any software entity that interacts with websites outside the entity itself,
 on behalf of its user,
 including simply rendering the content of websites.
 In web specifications and the rest of this document,
-web user agents are usually referred to as just "[=user agents=]",
-but there are other kinds of user agents in other domains,
-for example "mail user agents" in the context of email.
+web user agents are usually referred to as just "[=user agents=]".
+Either fully-qualified term can be used
+if there's a chance of confusion.
 A person can use many different user agents in their day-to-day life.
 
 The most common type of web user agent is the web browser,