diff --git a/VM/include/lualib.h b/VM/include/lualib.h
index 5db1625c..0237096b 100644
--- a/VM/include/lualib.h
+++ b/VM/include/lualib.h
@@ -26,7 +26,7 @@ LUALIB_API double luaL_checknumber(lua_State* L, int numArg);
 LUALIB_API double luaL_optnumber(lua_State* L, int nArg, double def);
 
 LUALIB_API bool luaL_checkboolean(lua_State* L, int narg);
-LUALIB_API bool luaL_optboolean(lua_State* L, int narg, bool default);
+LUALIB_API bool luaL_optboolean(lua_State* L, int narg, bool def);
 
 LUALIB_API int luaL_checkinteger(lua_State* L, int numArg);
 LUALIB_API int luaL_optinteger(lua_State* L, int nArg, int def);