diff --git a/lisp/gnus/nnimap.el b/lisp/gnus/nnimap.el
index 566c3e3fba4..2eb6751a211 100644
--- a/lisp/gnus/nnimap.el
+++ b/lisp/gnus/nnimap.el
@@ -448,13 +448,14 @@ during splitting, which may be slow."
 
 (defun nnimap-open-connection (buffer)
   ;; Be backwards-compatible -- the earlier value of nnimap-stream was
-  ;; `ssl' when nnimap-server-port was nil.  Sort of.
+  ;; `ssl' when nnimap-server-port was nil.  Sort of.  But it's `tls'
+  ;; now, because we're post the Great 2025 Spelling Reform.
   (when (and nnimap-server-port
 	     (eq nnimap-stream 'undecided))
-    (setq nnimap-stream 'ssl))
+    (setq nnimap-stream 'tls))
   (let ((stream
 	 (if (eq nnimap-stream 'undecided)
-	     (cl-loop for type in '(ssl network)
+	     (cl-loop for type in '(tls network)
 		   for stream = (let ((nnimap-stream type))
 				  (nnimap-open-connection-1 buffer))
 		   while (eq stream 'no-connect)
@@ -493,7 +494,7 @@ during splitting, which may be slow."
 	      (nnheader-message 7 "Opening connection to %s via shell..."
 				nnimap-address)
 	      '("imap"))
-	     ((memq nnimap-stream '(ssl tls))
+	     ((memq nnimap-stream '(tls ssl))
 	      (nnheader-message 7 "Opening connection to %s via tls..."
 				nnimap-address)
 	      '("imaps" "imap" "993" "143"))
diff --git a/lisp/mail/smtpmail.el b/lisp/mail/smtpmail.el
index 2461ddcfd0d..2acb48438ec 100644
--- a/lisp/mail/smtpmail.el
+++ b/lisp/mail/smtpmail.el
@@ -99,12 +99,15 @@ don't define this value."
   "Type of SMTP connections to use.
 This may be either nil (upgrade with STARTTLS if possible),
 `starttls' (refuse to send if STARTTLS isn't available),
-`plain' (never use STARTTLS), or `ssl' (to use TLS/SSL)."
+`plain' (never use STARTTLS), or `tls' (to use TLS/SSL).
+`ssl' is accepted as a backwards-compatible equivalent
+to `tls'"
   :version "24.1"
   :type '(choice (const :tag "Possibly upgrade to STARTTLS" nil)
 		 (const :tag "Always use STARTTLS" starttls)
 		 (const :tag "Never use STARTTLS" plain)
-		 (const :tag "Use TLS/SSL" ssl)))
+		 (const :tag "Use TLS/SSL" tls)
+		 (const :tag "Use TLS/SSL (old name)" ssl)))
 
 (defcustom smtpmail-sendto-domain nil
   "Local domain name without a host name.