A turban is a long scarf that's wrapped many times around a person's head. Men who are Sikh or Muslim traditionally wear turbans.
There is a smaller woman's hat also called a turban that's styled after the traditional turban. Sikhs are the most common wearers of turbans, including some sikh women (although theirs are usually called a Dahtar). Turbans cover long hair and help keep it clean, as well as representing a proud Sikh identity. In Islam, different types of turbans represent different beliefs or social statuses. Turban comes from a Persian root, dulband.