Modernize usage of 'macOS' in doc and comments

Apple changed the spelling of its operating system again, to "macOS",
effective with macOS 10.12 Sierra (2016-09-20).  Change Emacs
documentation and comments to match this.  Stick with older OS
spellings ("OS X", "Mac OS X") when talking about older releases where
the older names are more correct.

24 files changed, 58 insertions, 58 deletions

diff --git a/lisp/arc-mode.el b/lisp/arc-mode.el
index b5373c607d4..c42ca813e96 100644
--- a/lisp/arc-mode.el
+++ b/lisp/arc-mode.el
@@ -1646,7 +1646,7 @@ This doesn't recover lost files, it just undoes changes in the buffer itself."
         ;;   converts "\" to "/".
         ;; - For 0 generic: generic_to_unix_filename() downcases if there's
         ;;   no lower case already present, and converts "\" to "/".
-        ;; - For 'm' MacOS: macos_to_unix_filename() changes "/" to ":" and
+        ;; - For 'm' macOS: macos_to_unix_filename() changes "/" to ":" and
         ;;   ":" to "/"
         (setq fiddle (cond ((= ?M osid) t)
                            ((= 0 osid)  (string= efnname (upcase efnname)))))
diff --git a/lisp/battery.el b/lisp/battery.el
index b5e312f6c3e..20f3017fc45 100644
--- a/lisp/battery.el
+++ b/lisp/battery.el
@@ -22,10 +22,10 @@
 
 ;;; Commentary:
 
-;; There is at present support for GNU/Linux, OS X and Windows.  This
+;; There is at present support for GNU/Linux, macOS and Windows.  This
 ;; library supports both the `/proc/apm' file format of Linux version
 ;; 1.3.58 or newer and the `/proc/acpi/' directory structure of Linux
-;; 2.4.20 and 2.6.  Darwin (OS X) is supported by using the `pmset'
+;; 2.4.20 and 2.6.  Darwin (macOS) is supported by using the `pmset'
 ;; program.  Windows is supported by the GetSystemPowerStatus API call.
 
 ;;; Code:
@@ -600,7 +600,7 @@ The following %-sequences are provided:
           (cons ?t (or remaining-time "N/A")))))
 
 
-;;; `pmset' interface for Darwin (OS X).
+;;; `pmset' interface for Darwin (macOS).
 
 (defun battery-pmset ()
   "Get battery status information using `pmset'.
diff --git a/lisp/cedet/semantic/bovine/gcc.el b/lisp/cedet/semantic/bovine/gcc.el
index ec292395f12..b56b268ca0d 100644
--- a/lisp/cedet/semantic/bovine/gcc.el
+++ b/lisp/cedet/semantic/bovine/gcc.el
@@ -225,7 +225,7 @@ It should also include other symbols GCC was compiled with.")
         (setq semantic-lex-c-preprocessor-symbol-map nil))
     (dolist (D defines)
       (add-to-list 'semantic-lex-c-preprocessor-symbol-map D))
-    ;; Needed for parsing OS X libc
+    ;; Needed for parsing macOS libc
     (when (eq system-type 'darwin)
       (add-to-list 'semantic-lex-c-preprocessor-symbol-map '("__i386__" . "")))
     (when (featurep 'semantic/bovine/c)
diff --git a/lisp/faces.el b/lisp/faces.el
index b1ea0f0fc34..a84edab3615 100644
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -108,7 +108,7 @@ a font height that isn't optimal."
      "Courier 10 Pitch"
      ;; This looks good on MS-Windows and OS X.
      "Consolas"
-     ;; This looks good on OS X.  "Courier" looks good too, but is
+     ;; This looks good on macOS.  "Courier" looks good too, but is
      ;; jagged on GNU/Linux and so is listed later as "courier".
      "Courier Std"
      ;; Although these are anti-aliased, they are a bit faint compared
diff --git a/lisp/gnus/auth-source.el b/lisp/gnus/auth-source.el
index 52765ce6b31..df8f61ff380 100644
--- a/lisp/gnus/auth-source.el
+++ b/lisp/gnus/auth-source.el
@@ -423,13 +423,13 @@ with \"[a/b/c] \" if CHOICES is \(?a ?b ?c)."
     ;; Keychain collection matching any user, host, and protocol
     ((eq entry 'macos-keychain-generic)
      (auth-source-backend-parse '(:source (:macos-keychain-generic default))))
-    ;; take macos-keychain-internet:XYZ and recurse to get it as MacOS
+    ;; take macos-keychain-internet:XYZ and recurse to get it as macOS
     ;; Keychain "XYZ" matching any user, host, and protocol
     ((and (stringp entry) (string-match "^macos-keychain-internet:\\(.+\\)"
                                         entry))
      (auth-source-backend-parse `(:source (:macos-keychain-internet
                                            ,(match-string 1 entry)))))
-    ;; take macos-keychain-generic:XYZ and recurse to get it as MacOS
+    ;; take macos-keychain-generic:XYZ and recurse to get it as macOS
     ;; Keychain "XYZ" matching any user, host, and protocol
     ((and (stringp entry) (string-match "^macos-keychain-generic:\\(.+\\)"
                                         entry))
@@ -458,7 +458,7 @@ with \"[a/b/c] \" if CHOICES is \(?a ?b ?c)."
         :search-function #'auth-source-netrc-search
         :create-function #'auth-source-netrc-create)))
 
-    ;; the MacOS Keychain
+    ;; the macOS Keychain
     ((and
       (not (null (plist-get entry :source))) ; the source must not be nil
       (listp (plist-get entry :source))      ; and it must be a list
@@ -1666,7 +1666,7 @@ authentication tokens:
                                     &key backend create delete
                                     type max
                                     &allow-other-keys)
-  "Search the MacOS Keychain; spec is like `auth-source'.
+  "Search the macOS Keychain; spec is like `auth-source'.
 
 All search keys must match exactly.  If you need substring
 matching, do a wider search and narrow it down yourself.
@@ -1688,13 +1688,13 @@ Similarly, :host maps to \"-c HOST\" (the \"creator\" keychain
 field), :user maps to \"-a USER\", and :port maps to \"-s PORT\".
 
 Here's an example that looks for the first item in the default
-generic MacOS Keychain:
+generic macOS Keychain:
 
  (let ((auth-sources \\='(macos-keychain-generic)))
     (auth-source-search :max 1)
 
 Here's another that looks for the first item in the internet
-MacOS Keychain collection whose label is `gnus':
+macOS Keychain collection whose label is `gnus':
 
  (let ((auth-sources \\='(macos-keychain-internet)))
     (auth-source-search :max 1 :label \"gnus\")
@@ -1707,11 +1707,11 @@ entries for git.gnus.org:
 "
   ;; TODO
   (assert (not create) nil
-          "The MacOS Keychain auth-source backend doesn't support creation yet")
+          "The macOS Keychain auth-source backend doesn't support creation yet")
   ;; TODO
   ;; (macos-keychain-delete-item coll elt)
   (assert (not delete) nil
-          "The MacOS Keychain auth-source backend doesn't support deletion yet")
+          "The macOS Keychain auth-source backend doesn't support deletion yet")
 
   (let* ((coll (oref backend source))
          (max (or max 5000))     ; sanity check: default to stop at 5K
diff --git a/lisp/international/mule-cmds.el b/lisp/international/mule-cmds.el
index e7c7049cd0a..5008fd5f27b 100644
--- a/lisp/international/mule-cmds.el
+++ b/lisp/international/mule-cmds.el
@@ -2723,7 +2723,7 @@ See also `locale-charset-language-names', `locale-language-names',
       ;; On Darwin, file names are always encoded in utf-8, no matter
       ;; the locale.
       (setq default-file-name-coding-system 'utf-8)
-      ;; Mac OS X's Terminal.app by default uses utf-8 regardless of
+      ;; macOS's Terminal.app by default uses utf-8 regardless of
       ;; the locale.
       (when (and (null window-system)
                  (equal (getenv "TERM_PROGRAM" frame) "Apple_Terminal"))
diff --git a/lisp/international/ucs-normalize.el b/lisp/international/ucs-normalize.el
index 1e247c5dba5..29cd042eee9 100644
--- a/lisp/international/ucs-normalize.el
+++ b/lisp/international/ucs-normalize.el
@@ -624,7 +624,7 @@ COMPOSITION-PREDICATE will be used to compose region."
 
 ;;; coding-system definition
 (define-coding-system 'utf-8-hfs
-  "UTF-8 based coding system for MacOS HFS file names.
+  "UTF-8 based coding system for macOS HFS file names.
 The singleton characters in HFS normalization exclusion will not
 be decomposed."
   :coding-type 'utf-8
diff --git a/lisp/ls-lisp.el b/lisp/ls-lisp.el
index 85e91cdadc0..41587bfe144 100644
--- a/lisp/ls-lisp.el
+++ b/lisp/ls-lisp.el
@@ -75,7 +75,7 @@
         ((memq system-type '(hpux usg-unix-v irix berkeley-unix))
          'UNIX))        ; very similar to GNU
   ;; Anything else defaults to nil, meaning GNU.
-  "Platform to emulate: GNU (default), MacOS, MS-Windows, UNIX.
+  "Platform to emulate: GNU (default), macOS, MS-Windows, UNIX.
 Corresponding value is one of: nil, `MacOS', `MS-Windows', `UNIX'.
 Set this to your preferred value; it need not match the actual platform
 you are using.
diff --git a/lisp/mail/emacsbug.el b/lisp/mail/emacsbug.el
index ce3c50bce2b..86aefe4a6dd 100644
--- a/lisp/mail/emacsbug.el
+++ b/lisp/mail/emacsbug.el
@@ -72,7 +72,7 @@
 (defvar message-strip-special-text-properties)
 
 (defun report-emacs-bug-can-use-osx-open ()
-  "Return non-nil if the OS X \"open\" command is available for mailing."
+  "Return non-nil if the macOS \"open\" command is available for mailing."
   (and (featurep 'ns)
        (equal (executable-find "open") "/usr/bin/open")
        (memq system-type '(darwin))))
@@ -107,7 +107,7 @@ This requires you to be running either Gnome, KDE, or Xfce4."
 
 (defun report-emacs-bug-insert-to-mailer ()
   "Send the message to your preferred mail client.
-This requires either the OS X \"open\" command, or the freedesktop
+This requires either the macOS \"open\" command, or the freedesktop
 \"xdg-email\" command to be available."
   (interactive)
   (save-excursion
diff --git a/lisp/man.el b/lisp/man.el
index 5acf90baf28..94b9e0d04da 100644
--- a/lisp/man.el
+++ b/lisp/man.el
@@ -887,7 +887,7 @@ test/automated/man-tests.el in the emacs repository."
           (setq default-directory "/") ;; in case inherited doesn't exist
           ;; Actually for my `man' the arg is a regexp.
           ;; POSIX says it must be ERE and "man-db" seems to agree,
-          ;; whereas under MacOSX it seems to be BRE-style and doesn't
+          ;; whereas under macOS it seems to be BRE-style and doesn't
           ;; accept backslashes at all.  Let's not bother to
           ;; quote anything.
           (let ((process-environment (copy-sequence process-environment)))
diff --git a/lisp/menu-bar.el b/lisp/menu-bar.el
index 640395e8d7d..ba1bf34d1a5 100644
--- a/lisp/menu-bar.el
+++ b/lisp/menu-bar.el
@@ -1865,7 +1865,7 @@ key, a click, or a menu-item"))
       '(menu-item "Emacs Tutorial" help-with-tutorial
                   :help "Learn how to use Emacs"))
 
-    ;; In OS X it's in the app menu already.
+    ;; In macOS it's in the app menu already.
     ;; FIXME? There already is an "About Emacs" (sans ...) entry in the Help menu.
     (and (featurep 'ns)
          (not (eq system-type 'darwin))
diff --git a/lisp/net/ange-ftp.el b/lisp/net/ange-ftp.el
index d5c03e3f4ae..239da7829df 100644
--- a/lisp/net/ange-ftp.el
+++ b/lisp/net/ange-ftp.el
@@ -740,7 +740,7 @@ These mean that the FTP process should be (or already has been) killed."
   :type 'regexp)
 
 (defcustom ange-ftp-potential-error-msgs
-  ;; On Mac OS X we sometimes get things like:
+  ;; On macOS we sometimes get things like:
   ;;
   ;;     ftp> open ftp.nluug.nl
   ;;     Trying 2001:610:1:80aa:192:87:102:36...
diff --git a/lisp/net/browse-url.el b/lisp/net/browse-url.el
index be859283891..68258d41666 100644
--- a/lisp/net/browse-url.el
+++ b/lisp/net/browse-url.el
@@ -44,7 +44,7 @@
 ;; browse-url-text-*                  Any text browser     0
 ;; browse-url-generic                 arbitrary
 ;; browse-url-default-windows-browser MS-Windows browser
-;; browse-url-default-macosx-browser  Mac OS X browser
+;; browse-url-default-macosx-browser  macOS browser
 ;; browse-url-xdg-open                Free Desktop xdg-open on Gnome, KDE, Xfce4, LXDE
 ;; browse-url-kde                     KDE konqueror (kfm)
 ;; browse-url-elinks                  Elinks      Don't know (tried with 0.12.GIT)
@@ -162,7 +162,7 @@ regexp should probably be \".\" to specify a default browser."
                          :value browse-url-generic)
           (function-item :tag "Default Windows browser"
                          :value browse-url-default-windows-browser)
-          (function-item :tag "Default Mac OS X browser"
+          (function-item :tag "Default macOS browser"
                          :value browse-url-default-macosx-browser)
           (function-item :tag "Default browser"
                          :value browse-url-default-browser)
@@ -870,7 +870,7 @@ The optional NEW-WINDOW argument is not used."
         (t (w32-shell-execute "open" url))))
 
 (defun browse-url-default-macosx-browser (url &optional _new-window)
-  "Invoke the MacOS X system's default Web browser.
+  "Invoke the macOS system's default Web browser.
 The optional NEW-WINDOW argument is not used"
   (interactive (browse-url-interactive-arg "URL: "))
   (start-process (concat "open " url) nil "open" url))
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 2983d402fa3..842b1ce2880 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -1272,7 +1272,7 @@ target of the symlink differ."
                  res-uid res-gid res-size res-symlink-target)
     (tramp-message vec 5 "file attributes with ls: %s" localname)
     ;; We cannot send all three commands combined, it could exceed
-    ;; NAME_MAX or PATH_MAX.  Happened on Mac OS X, for example.
+    ;; NAME_MAX or PATH_MAX.  Happened on macOS, for example.
     (when (or (tramp-send-command-and-check
                vec
                (format "%s %s"
@@ -4263,7 +4263,7 @@ process to set up.  VEC specifies the connection."
             (when (search-forward "\r" nil t)
               (setq cs-decode (tramp-compat-coding-system-change-eol-conversion
                                cs-decode 'dos)))
-            ;; Special setting for Mac OS X.
+            ;; Special setting for macOS.
             (when (and (string-match "^Darwin" uname)
                        (memq 'utf-8-hfs (coding-system-list)))
               (setq cs-decode 'utf-8-hfs
@@ -4325,7 +4325,7 @@ process to set up.  VEC specifies the connection."
         (tramp-send-command vec "stty tabs" t)
       (tramp-send-command vec "stty tab0" t))
 
-    ;; Set utf8 encoding.  Needed for Mac OS X, for example.  This is
+    ;; Set utf8 encoding.  Needed for macOS, for example.  This is
     ;; non-POSIX, so we must expect errors on some systems.
     (tramp-send-command vec "stty iutf8 2>/dev/null" t)
 
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index cb8e4d4d4c3..5d8081cd815 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -1018,7 +1018,7 @@ this variable to be set as well."
   :type '(choice (const nil) integer))
 
 ;; Logging in to a remote host normally requires obtaining a pty.  But
-;; Emacs on MacOS X has process-connection-type set to nil by default,
+;; Emacs on macOS has process-connection-type set to nil by default,
 ;; so on those systems Tramp doesn't obtain a pty.  Here, we allow
 ;; for an override of the system default.
 (defcustom tramp-process-connection-type t
diff --git a/lisp/org/org.el b/lisp/org/org.el
index 13e4a222131..eb01426533d 100644
--- a/lisp/org/org.el
+++ b/lisp/org/org.el
@@ -1937,7 +1937,7 @@ See `org-file-apps'.")
     ("eps.gz" . "gv %s")
     ("dvi"    . "xdvi %s")
     ("fig"    . "xfig %s"))
-  "Default file applications on a MacOS X system.
+  "Default file applications on a macOS system.
 The system \"open\" is known as a default, but we use X11 applications
 for some files for which the OS does not have a good default.
 See `org-file-apps'.")
@@ -2012,7 +2012,7 @@ file identifier are
                (\"html\" . default) to the list as well.
  t             Default for files not matched by any of the other options.
  `system'      The system command to open files, like `open' on Windows
-               and Mac OS X, and mailcap under GNU/Linux.  This is the command
+               and macOS, and mailcap under GNU/Linux.  This is the command
                that will be selected if you call `C-c C-o' with a double
                \\[universal-argument] \\[universal-argument] prefix.
 
diff --git a/lisp/printing.el b/lisp/printing.el
index d9cc2a3614a..72f825fcb89 100644
--- a/lisp/printing.el
+++ b/lisp/printing.el
@@ -2272,7 +2272,7 @@ Useful links:
 * gv 3.5, June 1997
   `http://www.cs.wisc.edu/~ghost/gv/gv_doc/gv.html'
 
-* MacGSView (MacOS)
+* MacGSView (Mac OS)
   `http://www.cs.wisc.edu/~ghost/macos/index.htm'
 "
   :type '(string :tag "Ghostview Utility")
diff --git a/lisp/progmodes/gdb-mi.el b/lisp/progmodes/gdb-mi.el
index d243650d73a..978b81699fc 100644
--- a/lisp/progmodes/gdb-mi.el
+++ b/lisp/progmodes/gdb-mi.el
@@ -69,12 +69,12 @@
 ;;   2) Use MinGW GDB instead.
 ;;   3) Use cygwin-mount.el
 
-;;; Mac OSX:
+;;; macOS:
 
-;; GDB in Emacs on Mac OSX works best with FSF GDB as Apple have made
-;; some changes to the version that they include as part of Mac OSX.
-;; This requires GDB version 7.0 or later (estimated release date Aug 2009)
-;; as earlier versions do not compile on Mac OSX.
+;; GDB in Emacs on macOS works best with FSF GDB as Apple have made
+;; some changes to the version that they include as part of macOS.
+;; This requires GDB version 7.0 or later as earlier versions do not
+;; compile on macOS.
 
 ;;; Known Bugs:
 
diff --git a/lisp/progmodes/idlwave.el b/lisp/progmodes/idlwave.el
index 9cb2ca74063..bc607ac4019 100644
--- a/lisp/progmodes/idlwave.el
+++ b/lisp/progmodes/idlwave.el
@@ -420,22 +420,22 @@ A value of t means to show all source files."
   :type 'integer)
 
 (defcustom idlwave-library-path nil
-  "Library path for Windows and MacOS (OS9).  Not needed under UNIX.
+  "Library path for Windows and Mac OS (OS9).  Not needed under UNIX.
 When selecting the directories to scan for IDL user catalog routine
 info, IDLWAVE can, under UNIX, query the shell for the exact search
-path \(the value of !PATH).  However, under Windows and MacOS
-\(pre-OSX), the IDLWAVE shell does not work.  In this case, this
-variable can be set to specify the paths where IDLWAVE can find PRO
-files.  The shell will only be asked for a list of paths when this
-variable is nil.  The value is a list of directories.  A directory
+path (the value of !PATH).  However, under MS-Windows, the
+IDLWAVE shell does not work.  In this case, this variable can be
+set to specify the paths where IDLWAVE can find PRO files.  The
+shell will only be asked for a list of paths when this variable
+is nil.  The value is a list of directories.  A directory
 preceded by a `+' will be searched recursively.  If you set this
-variable on a UNIX system, the shell will not be queried.  See also
-`idlwave-system-directory'."
+variable on a UNIX system, the shell will not be queried.  See
+also `idlwave-system-directory'."
   :group 'idlwave-routine-info
   :type '(repeat (directory)))
 
 (defcustom idlwave-system-directory ""
-  "The IDL system directory for Windows and MacOS.  Not needed under
+  "The IDL system directory for Windows and Mac OS.  Not needed under
 UNIX.  Set this to the value of the `!DIR' system variable in IDL.
 IDLWAVE uses this to find out which of the library routines belong to
 the official system library.  All files inside the `lib' subdirectory
diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 3fae3987b22..8ec9febe5c9 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -2414,7 +2414,7 @@ banner and the initial prompt are received separately."
 (defun python-shell-comint-end-of-output-p (output)
   "Return non-nil if OUTPUT is ends with input prompt."
   (string-match
-   ;; XXX: It seems on OSX an extra carriage return is attached
+   ;; XXX: It seems on macOS an extra carriage return is attached
    ;; at the end of output, this handles that too.
    (concat
     "\r?\n?"
diff --git a/lisp/term/ns-win.el b/lisp/term/ns-win.el
index e737131d5bf..21bba480d02 100644
--- a/lisp/term/ns-win.el
+++ b/lisp/term/ns-win.el
@@ -1,4 +1,4 @@
-;;; ns-win.el --- lisp side of interface with NeXT/Open/GNUstep/MacOS X window system  -*- lexical-binding: t -*-
+;;; ns-win.el --- lisp side of interface with NeXT/Open/GNUstep/macOS window system  -*- lexical-binding: t -*-
 
 ;; Copyright (C) 1993-1994, 2005-2016 Free Software Foundation, Inc.
 
@@ -41,7 +41,7 @@
 ;;; Code:
 (eval-when-compile (require 'cl-lib))
 (or (featurep 'ns)
-    (error "%s: Loading ns-win.el but not compiled for GNUstep/MacOS"
+    (error "%s: Loading ns-win.el but not compiled for GNUstep/macOS"
            (invocation-name)))
 
 ;; Documentation-purposes only: actually loaded in loadup.el.
@@ -54,7 +54,7 @@
 (require 'ucs-normalize)
 
 (defgroup ns nil
-  "GNUstep/Mac OS X specific features."
+  "GNUstep/macOS specific features."
   :group 'environment)
 
 ;;;; Command line argument handling.
@@ -338,7 +338,7 @@ See `ns-insert-working-text'."
   (setq ns-working-overlay nil))
 
 
-;; OS X file system Unicode UTF-8 NFD (decomposed form) support.
+;; macOS file system Unicode UTF-8 NFD (decomposed form) support.
 (when (eq system-type 'darwin)
   ;; Used prior to Emacs 25.
   (define-coding-system-alias 'utf-8-nfd 'utf-8-hfs)
@@ -641,7 +641,7 @@ This function has been overloaded in Nextstep.")
   (set-frame-font ns-input-font))
 
 
-;; Default fontset for Mac OS X.  This is mainly here to show how a fontset
+;; Default fontset for macOS.  This is mainly here to show how a fontset
 ;; can be set up manually.  Ordinarily, fontsets are auto-created whenever
 ;; a font is chosen by
 (defvar ns-standard-fontset-spec
@@ -655,7 +655,7 @@ This function has been overloaded in Nextstep.")
              ",")
   "String of fontset spec of the standard fontset.
 This defines a fontset consisting of the Courier and other fonts that
-come with OS X.
+come with macOS.
 See the documentation of `create-fontset-from-fontset-spec' for the format.")
 
 (defvar ns-reg-to-script)               ; nsfont.m
@@ -892,7 +892,7 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
                     (setq default-process-coding-system
                           '(utf-8-unix . utf-8-unix)))))
 
-  ;; OS X Lion introduces PressAndHold, which is unsupported by this port.
+  ;; Mac OS X Lion introduces PressAndHold, which is unsupported by this port.
   ;; See this thread for more details:
   ;; http://lists.gnu.org/archive/html/emacs-devel/2011-06/msg00505.html
   (ns-set-resource nil "ApplePressAndHoldEnabled" "NO")
diff --git a/lisp/term/xterm.el b/lisp/term/xterm.el
index 19eb37a51d6..880141bda12 100644
--- a/lisp/term/xterm.el
+++ b/lisp/term/xterm.el
@@ -771,7 +771,7 @@ We run the first FUNCTION whose STRING matches the input events."
       ;; Try to find out the type of terminal by sending a "Secondary
       ;; Device Attributes (DA)" query.
       (xterm--query "\e[>0c"
-                    ;; Some terminals (like OS X's Terminal.app) respond to
+                    ;; Some terminals (like macOS's Terminal.app) respond to
                     ;; this query as if it were a "Primary Device Attributes"
                     ;; query instead, so we should handle that too.
                     '(("\e[?" . xterm--version-handler)
diff --git a/lisp/textmodes/rst.el b/lisp/textmodes/rst.el
index 3d4854e89d6..aea8e7072ea 100644
--- a/lisp/textmodes/rst.el
+++ b/lisp/textmodes/rst.el
@@ -645,7 +645,7 @@ as well but give an additional message."
     ;;
     ;; The adjustment function that adorns or rotates a section title.
     (rst-define-key map [?\C-c ?\C-=] 'rst-adjust [?\C-c ?\C-a t])
-    (rst-define-key map [?\C-=] 'rst-adjust) ; Does not work on the Mac OSX and
+    (rst-define-key map [?\C-=] 'rst-adjust) ; Does not work on macOS and
                                              ; on consoles.
 
     ;; \C-c \C-a is the keymap for adornments.
diff --git a/lisp/vc/pcvs.el b/lisp/vc/pcvs.el
index 573feedd047..b0ad5ea588d 100644
--- a/lisp/vc/pcvs.el
+++ b/lisp/vc/pcvs.el
@@ -551,7 +551,7 @@ If non-nil, NEW means to create a new buffer no matter what."
                ;; is accessed via SSH, a bad interaction between libc,
                ;; CVS and SSH can lead to garbled output.
                ;; It might be a glibc-specific problem (but it can also happens
-               ;; under Mac OS X, it seems).
+               ;; under macOS, it seems).
                ;; It seems that using a pty can help circumvent the problem,
                ;; but at the cost of screwing up when the process thinks it
                ;; can ask for user input (such as password or host-key
@@ -696,7 +696,7 @@ SUBDIR is the subdirectory (if any) where this command was run.
 OLD-FIS is the list of fileinfos on which the cvs command was applied and
   which should be considered up-to-date if they are missing from the output."
   (when (eq system-type 'darwin)
-    ;; Fixup the ^D^H^H inserted at beginning of buffer sometimes on MacOSX
+    ;; Fixup the ^D^H^H inserted at beginning of buffer sometimes on macOS
     ;; because of the call to `process-send-eof'.
     (save-excursion
       (goto-char (point-min))