diff --git a/htdocs/langs/en_US/main.lang b/htdocs/langs/en_US/main.lang
index 1096b9857f1..84d399ddde2 100644
--- a/htdocs/langs/en_US/main.lang
+++ b/htdocs/langs/en_US/main.lang
@@ -646,6 +646,7 @@ SupplierPreview=Vendor preview
 ShowCustomerPreview=Show customer preview
 ShowSupplierPreview=Show vendor preview
 RefCustomer=Ref. customer
+InternalRef=Internal ref.
 Currency=Currency
 InfoAdmin=Information for administrators
 Undo=Undo