diff --git a/include/mruby/object.h b/include/mruby/object.h
index a9a9a43d1..57e56dc83 100644
--- a/include/mruby/object.h
+++ b/include/mruby/object.h
@@ -11,7 +11,7 @@
   struct RClass *c;       \
   struct RBasic *gcnext;  \
   enum mrb_vtype tt:8;    \
-  unsigned int gccolor:3; \
+  unsigned int gc_color:3; \
   unsigned int frozen:1;  \
   uint32_t flags:20
 
diff --git a/src/class.c b/src/class.c
index 1c7e2f162..1ad243fd2 100644
--- a/src/class.c
+++ b/src/class.c
@@ -790,7 +790,7 @@ mrb_define_method_raw(mrb_state *mrb, struct RClass *c, mrb_sym mid, mrb_method_
 
     ptr.proc = p;
     if (p) {
-      if (p->gccolor != MRB_GC_RED) {
+      if (p->gc_color != MRB_GC_RED) {
         p->flags |= MRB_PROC_SCOPE;
         p->c = NULL;
         mrb_field_write_barrier(mrb, (struct RBasic*)c, (struct RBasic*)p);
diff --git a/src/gc.c b/src/gc.c
index 562c081a8..32fb7027b 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -170,17 +170,17 @@ typedef struct mrb_heap_page {
 #define GC_COLOR_MASK 7
 mrb_static_assert(MRB_GC_RED <= GC_COLOR_MASK);
 
-#define paint_gray(o) ((o)->gccolor = GC_GRAY)
-#define paint_black(o) ((o)->gccolor = GC_BLACK)
-#define paint_white(o) ((o)->gccolor = GC_WHITES)
-#define paint_partial_white(s, o) ((o)->gccolor = (s)->current_white_part)
-#define is_gray(o) ((o)->gccolor == GC_GRAY)
-#define is_white(o) ((o)->gccolor & GC_WHITES)
-#define is_black(o) ((o)->gccolor == GC_BLACK)
-#define is_red(o) ((o)->gccolor == GC_RED)
+#define paint_gray(o) ((o)->gc_color = GC_GRAY)
+#define paint_black(o) ((o)->gc_color = GC_BLACK)
+#define paint_white(o) ((o)->gc_color = GC_WHITES)
+#define paint_partial_white(s, o) ((o)->gc_color = (s)->current_white_part)
+#define is_gray(o) ((o)->gc_color == GC_GRAY)
+#define is_white(o) ((o)->gc_color & GC_WHITES)
+#define is_black(o) ((o)->gc_color == GC_BLACK)
+#define is_red(o) ((o)->gc_color == GC_RED)
 #define flip_white_part(s) ((s)->current_white_part = other_white_part(s))
 #define other_white_part(s) ((s)->current_white_part ^ GC_WHITES)
-#define is_dead(s, o) (((o)->gccolor & other_white_part(s) & GC_WHITES) || (o)->tt == MRB_TT_FREE)
+#define is_dead(s, o) (((o)->gc_color & other_white_part(s) & GC_WHITES) || (o)->tt == MRB_TT_FREE)
 
 mrb_noreturn void mrb_raise_nomemory(mrb_state *mrb);