diff --git a/include/picrin.h b/include/picrin.h
index e8fb24b2..7588ec61 100644
--- a/include/picrin.h
+++ b/include/picrin.h
@@ -66,7 +66,7 @@ typedef struct {
   jmp_buf *jmp;
   const char *errmsg;
 
-  struct heap_page *heap;
+  struct pic_heap *heap;
   struct pic_object *arena[PIC_ARENA_SIZE];
   int arena_idx;
 
diff --git a/include/picrin/gc.h b/include/picrin/gc.h
index beea808c..76c029ca 100644
--- a/include/picrin/gc.h
+++ b/include/picrin/gc.h
@@ -15,11 +15,11 @@ union header {
   long alignment;   /* force alignment for headers to be allocated at the size of long */
 };
 
-struct heap_page {
+struct pic_heap {
   union header base, *freep;
   size_t heap_size;
 };
 
-void init_heap_page(struct heap_page *);
+void init_heap(struct pic_heap *);
 
 #endif
diff --git a/src/gc.c b/src/gc.c
index fa8ca17d..d5ec4f22 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -14,7 +14,7 @@
 #endif
 
 void
-init_heap_page(struct heap_page *heap)
+init_heap(struct pic_heap *heap)
 {
   heap->base.s.ptr = heap->freep = &heap->base;
   heap->base.s.size = 0;	/* not 1, since it must never be fused into other headers */
diff --git a/src/state.c b/src/state.c
index e85f435b..d8db2f75 100644
--- a/src/state.c
+++ b/src/state.c
@@ -43,8 +43,8 @@ pic_open(int argc, char *argv[], char **envp)
   pic->rlen = PIC_RESCUE_SIZE;
 
   /* memory heap */
-  pic->heap = (struct heap_page *)calloc(1, sizeof(struct heap_page));
-  init_heap_page(pic->heap);
+  pic->heap = (struct pic_heap *)calloc(1, sizeof(struct pic_heap));
+  init_heap(pic->heap);
 
   /* symbol table */
   pic->sym_tbl = xh_new();