diff --git a/m-dict.h b/m-dict.h
index aa04cd10..5e3d7856 100644
--- a/m-dict.h
+++ b/m-dict.h
@@ -156,7 +156,7 @@
 /*****************************************************************************/
 
 // Define the maximum index
-#ifdef M_USE_64BITS_INDEX
+#ifdef M_USE_DICT_LARGE_INDEX
 typedef uint64_t m_index_t;
 #else
 typedef uint32_t m_index_t;