The extended piece of fabric that trails on the floor at the back of a bridal gown or wedding dress is known as the train.
Bridal gown train lengths and styles vary depending on the formality of the wedding and the preference of the bride. The different train lengths are identified with specific names within the bridal industry as described in this article:
Wedding Dress Train Styles
Get the full scoop Here are different style lengths of various wedding gown trains.« View Entire Wedding Glossary