diff --git a/src/namedef_custom.h b/src/namedef_custom.h
index 1c188007ce..0343e307d4 100644
--- a/src/namedef_custom.h
+++ b/src/namedef_custom.h
@@ -859,3 +859,23 @@ xx(Exclude)
 xx(Userstring)
 xx(Sky)
 xx(Pagename)
+
+// Lightmap keywords
+//xx(lightcolor) // already defined
+xx(lightintensity)
+xx(lightdistance)
+xx(lightinnerangle)
+xx(lightouterangle)
+xx(lightcolorfloor)
+xx(lightintensityfloor)
+xx(lightdistancefloor)
+xx(lightcolorceiling)
+xx(lightintensityceiling)
+xx(lightdistanceceiling)
+xx(suncolor)
+xx(sundirx)
+xx(sundiry)
+xx(sundirz)
+xx(sampledistance)
+xx(bounces)
+xx(gridsize)