diff --git a/Modules/main.c b/Modules/main.c
index 8e02fe4..38b6223 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -390,7 +390,7 @@
 			skipfirstline = 1;
 			break;
 
-		/* case 'X': reserved for non-standard arguments */
+		/* case 'X': reserved for implementation-specific arguments */
 
 		case 'U':
 			Py_UnicodeFlag++;
diff --git a/Python/getopt.c b/Python/getopt.c
index acdd5d7..247600b 100644
--- a/Python/getopt.c
+++ b/Python/getopt.c
@@ -88,7 +88,7 @@
 
 	if (option == 'X') {
 		fprintf(stderr,
-			"-X is reserved for non-standard arguments\n");
+		  "-X is reserved for implementation-specific arguments\n");
 		return '_';
 	}