Musannaf Ibn Abi Shayba 3:3799

Abu Khalid narrated to us, from Ash'ath, from Muhammad, from Ubaydah, who said: "The woman prays in a chemise (dir'), a head covering (khimar), and a waist-wrapper (hiqw)." Ash'ath said from Muhammad the like of it. I said to him: "What is this khimar?" He said: "The khimar is that which covers." And the Ansar used to call the waist-wrapper (izar) the hiqw.