According to the Glorious Quran, the word refers to the bran that covers wheat seeds. Husk turns into ash after wheat seeds are harvested. The word occurs in the Glorious Quran in the incident of Ashaab Al-Feel (People of the Elephant). The reference means to symbolize Allah’s punishment, as He demolished the assaulters utterly that they became like crushed stalk and straw.
(And He made them like eaten straw) [Al-Feel: 5]