Musannaf Ibn Abi Shaybah

Muhammad narrates that Hazrat Ubaidah said that a woman will pray in a shirt, a sheet, and a "haqu." The narrator says that I asked Hazrat Ash'ath, "What are these sheets?" He replied, "A sheet is that which covers the body." I asked, "What is this 'haqu'?" He replied, "The Ansar used to call the izar (lower garment) 'haqu'."