Haute Couture (ot-koo-toor) is French for high fashion. Each piece is tailored for a specific client. It is handmade and it is of the highest quality that is why it is very expensive.
This is the opposite of Prêt-à-Porter. Prêt-à-Porter (predapor-tā) means ready-to-wear. It is factory made and produced in big quantities with different standard sizes.