diff --git a/collects/scribblings/reference/runtime.scrbl b/collects/scribblings/reference/runtime.scrbl
index 84417a4894..edc9beceec 100644
--- a/collects/scribblings/reference/runtime.scrbl
+++ b/collects/scribblings/reference/runtime.scrbl
@@ -18,9 +18,9 @@ contain a null character; the environment variable named by
 @racket[name] is set to @racket[value]. The return value is
 @racket[#t] if the assignment succeeds, @racket[#f] otherwise.}
 
-@defproc[(system-type [mode (or/c 'os 'gc 'link 'so-suffix 'machine)
+@defproc[(system-type [mode (or/c 'os 'word 'gc 'link 'so-suffix 'machine)
                             'os])
-         (or/c symbol? string? bytes?)]{
+         (or/c symbol? string? bytes? exact-positive-integer?)]{
 
 Returns information about the operating system, build mode, or machine
 for a running Racket.
@@ -34,6 +34,10 @@ In @indexed-racket['os] mode,
 @item{@indexed-racket['macosx]}
 ]
 
+In @indexed-racket['word] mode, the result is either @racket[32] or
+@racket[64] to indicate whether Racket is running as a 32-bit program
+or 64-bit program.
+
 In @indexed-racket['gc] mode,
 the possible symbol results are:
 
diff --git a/collects/tests/racket/basic.rktl b/collects/tests/racket/basic.rktl
index 93cdde8215..70afe27c51 100644
--- a/collects/tests/racket/basic.rktl
+++ b/collects/tests/racket/basic.rktl
@@ -2572,6 +2572,9 @@
 (test #t symbol? (system-type 'link))
 (test #t relative-path? (system-library-subpath))
 
+(test #t pair? (memv (system-type 'word) '(32 64)))
+(test (fixnum? (expt 2 32)) = (system-type 'word) 64)
+
 (test #t 'cmdline (let ([v (current-command-line-arguments)])
 		    (and (vector? v)
 			 (andmap string? (vector->list v)))))
diff --git a/collects/typed-racket/base-env/base-env.rkt b/collects/typed-racket/base-env/base-env.rkt
index 626b7d78b9..85b7be72f9 100644
--- a/collects/typed-racket/base-env/base-env.rkt
+++ b/collects/typed-racket/base-env/base-env.rkt
@@ -1146,7 +1146,8 @@
   (-> (-val 'gc) (Un (-val 'cgc) (-val '3m)))
   (-> (-val 'link) (Un (-val 'static) (-val 'shared) (-val 'dll) (-val 'framework)))
   (-> (-val 'so-suffix) -Bytes)
-  (-> (-val 'machine) -String))]
+  (-> (-val 'machine) -String)
+  (-> (-val 'word) -PosInt))]
 [system-language+country (-> -String)]
 [system-library-subpath (->opt [(Un (-val #f) (-val 'cgc) (-val '3m))] -Path)]
 
diff --git a/doc/release-notes/racket/HISTORY.txt b/doc/release-notes/racket/HISTORY.txt
index 9a6001cf86..3d5c03aef8 100644
--- a/doc/release-notes/racket/HISTORY.txt
+++ b/doc/release-notes/racket/HISTORY.txt
@@ -1,5 +1,7 @@
 Version 5.3.1.10
 Added phantom byte strings
+Added 'word mode to system-type
+racket/gui: added display-changed to frame%
 
 Version 5.3.1.9
 Changed case to use equal? instead of eqv?
diff --git a/src/racket/src/string.c b/src/racket/src/string.c
index ab996c12c6..839a70dc17 100644
--- a/src/racket/src/string.c
+++ b/src/racket/src/string.c
@@ -2349,9 +2349,14 @@ static Scheme_Object *system_type(int argc, Scheme_Object *argv[])
 #endif
     }
 
+    sym = scheme_intern_symbol("word");
+    if (SAME_OBJ(argv[0], sym)) {
+      return scheme_make_integer(sizeof(void*)*8);
+    }
+
     sym = scheme_intern_symbol("os");
     if (!SAME_OBJ(argv[0], sym)) {
-      scheme_wrong_contract("system-type", "(or/c 'os 'link 'machine 'gc 'so-suffix)", 0, argc, argv);
+      scheme_wrong_contract("system-type", "(or/c 'os 'word 'link 'machine 'gc 'so-suffix 'word)", 0, argc, argv);
       return NULL;
     }
   }