The niqab (Arabic) is a face veil worn by Muslim women. It comes originally from Bedouin culture in the Arabian Peninsula and has been already used in pre-Islamic time by men and women in order to protect the face from sun and sand.
Usually it is worn in conjunction with a black robe, the chador. The smaller the field of visible skin around the eyes, the more similar the niqab is to a burka, which is a garment that covers body and face completely.
Women wearing the niqab are called "niqabi".