diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 79fb72a464d..7ab2896778d 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -646,9 +646,9 @@ If the value is zero, then command input is not echoed.
 
 @defvar message-truncate-lines
 Normally, displaying a long message resizes the echo area to display
-the entire message.  But if the variable @code{message-truncate-lines}
-is non-@code{nil}, the echo area does not resize, and the message is
-truncated to fit it.
+the entire message, wrapping long line as needed.  But if the variable
+@code{message-truncate-lines} is non-@code{nil}, long lines of
+echo-area message are instead truncated to fit the mini-window width.
 @end defvar
 
   The variable @code{max-mini-window-height}, which specifies the
diff --git a/src/xdisp.c b/src/xdisp.c
index 0846af268eb..e853c8c2232 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -35445,7 +35445,7 @@ and `scroll-right' overrides this variable's effect.  */);
   Vhscroll_step = make_fixnum (0);
 
   DEFVAR_BOOL ("message-truncate-lines", message_truncate_lines,
-    doc: /* If non-nil, messages are truncated instead of resizing the echo area.
+    doc: /* If non-nil, messages are truncated when displaying the echo area.
 Bind this around calls to `message' to let it take effect.  */);
   message_truncate_lines = false;