diff --git a/code/renderer/tr_backend.c b/code/renderer/tr_backend.c
index f327db0e..ac321b34 100644
--- a/code/renderer/tr_backend.c
+++ b/code/renderer/tr_backend.c
@@ -576,7 +576,7 @@ void RB_RenderDrawSurfList( drawSurf_t *drawSurfs, int numDrawSurfs ) {
 		if ( entityNum != oldEntityNum ) {
 			depthRange = isCrosshair = qfalse;
 
-			if ( entityNum != ENTITYNUM_WORLD ) {
+			if ( entityNum != REFENTITYNUM_WORLD ) {
 				backEnd.currentEntity = &backEnd.refdef.entities[entityNum];
 				backEnd.refdef.floatTime = originalTime - backEnd.currentEntity->e.shaderTime;
 				// we have to reset the shaderTime as well otherwise image animations start
diff --git a/code/renderer/tr_main.c b/code/renderer/tr_main.c
index e6ab2533..b134345d 100644
--- a/code/renderer/tr_main.c
+++ b/code/renderer/tr_main.c
@@ -679,7 +679,7 @@ qboolean R_GetPortalOrientations( drawSurf_t *drawSurf, int entityNum,
 	R_PlaneForSurface( drawSurf->surface, &originalPlane );
 
 	// rotate the plane if necessary
-	if ( entityNum != ENTITYNUM_WORLD ) {
+	if ( entityNum != REFENTITYNUM_WORLD ) {
 		tr.currentEntityNum = entityNum;
 		tr.currentEntity = &tr.refdef.entities[entityNum];
 
@@ -796,7 +796,7 @@ static qboolean IsMirror( const drawSurf_t *drawSurf, int entityNum )
 	R_PlaneForSurface( drawSurf->surface, &originalPlane );
 
 	// rotate the plane if necessary
-	if ( entityNum != ENTITYNUM_WORLD ) 
+	if ( entityNum != REFENTITYNUM_WORLD )
 	{
 		tr.currentEntityNum = entityNum;
 		tr.currentEntity = &tr.refdef.entities[entityNum];
diff --git a/code/renderer/tr_scene.c b/code/renderer/tr_scene.c
index d1d34e3c..fcbbe500 100644
--- a/code/renderer/tr_scene.c
+++ b/code/renderer/tr_scene.c
@@ -100,7 +100,7 @@ void R_AddPolygonSurfaces( void ) {
 	shader_t	*sh;
 	srfPoly_t	*poly;
 
-	tr.currentEntityNum = ENTITYNUM_WORLD;
+	tr.currentEntityNum = REFENTITYNUM_WORLD;
 	tr.shiftedEntityNum = tr.currentEntityNum << QSORT_ENTITYNUM_SHIFT;
 
 	for ( i = 0, poly = tr.refdef.polys; i < tr.refdef.numPolys ; i++, poly++ ) {
diff --git a/code/renderer/tr_types.h b/code/renderer/tr_types.h
index 2706b76b..d30e608a 100644
--- a/code/renderer/tr_types.h
+++ b/code/renderer/tr_types.h
@@ -27,7 +27,10 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #define	MAX_DLIGHTS		32		// can't be increased, because bit flags are used on surfaces
 
 #define	ENTITYNUM_BITS		10		// can't be increased without changing drawsurf bit packing
+// the last N-bit number (2^ENTITYNUM_BITS - 1) is reserved for the special world refentity,
+//  and this is reflected by the value of MAX_ENTITIES (which therefore is not a power-of-2)
 #define	MAX_ENTITIES		((1<<ENTITYNUM_BITS) - 1)
+#define	REFENTITYNUM_WORLD	((1<<ENTITYNUM_BITS) - 1)
 
 // renderfx flags
 #define	RF_MINLIGHT		0x0001		// allways have some light (viewmodel, some items)
diff --git a/code/renderer/tr_world.c b/code/renderer/tr_world.c
index 9818883c..11375103 100644
--- a/code/renderer/tr_world.c
+++ b/code/renderer/tr_world.c
@@ -58,7 +58,7 @@ static qboolean	R_CullGrid( srfGridMesh_t *cv ) {
 		return qtrue;
 	}
 
-	if ( tr.currentEntityNum != ENTITYNUM_WORLD ) {
+	if ( tr.currentEntityNum != REFENTITYNUM_WORLD ) {
 		sphereCull = R_CullLocalPointAndRadius( cv->localOrigin, cv->meshRadius );
 	} else {
 		sphereCull = R_CullPointAndRadius( cv->localOrigin, cv->meshRadius );
@@ -651,7 +651,7 @@ void R_AddWorldSurfaces (void) {
 		return;
 	}
 
-	tr.currentEntityNum = ENTITYNUM_WORLD;
+	tr.currentEntityNum = REFENTITYNUM_WORLD;
 	tr.shiftedEntityNum = tr.currentEntityNum << QSORT_ENTITYNUM_SHIFT;
 
 	// determine which leaves are in the PVS / areamask