diff --git a/src/xdisp.c b/src/xdisp.c
index 45ed4c8c461..d103230a698 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -14861,7 +14861,7 @@ vertical margin.  */);
   Vtool_bar_button_margin = make_number (DEFAULT_TOOL_BAR_BUTTON_MARGIN);
 
   DEFVAR_INT ("tool-bar-button-relief", &tool_bar_button_relief,
-    doc: /* Relief thickness of tool-bar buttons.  */);
+    doc: /* *Relief thickness of tool-bar buttons.  */);
   tool_bar_button_relief = DEFAULT_TOOL_BAR_BUTTON_RELIEF;
 
   DEFVAR_LISP ("fontification-functions", &Vfontification_functions,