(a) The niqāb—its plural is nuqub, on the pattern of kitāb/kutub—is a khimār that veils a woman’s face while the cloth rests on the bridge of the nose, leaving only the eye sockets exposed.
(b) The burquʿ (with ḍamma on the bāʾ and a silent rāʾ; pl. barāqiʿ) is likewise a face-covering khimār, but it contains two small holes the size of the eyes, so its opening is narrower than that of the niqāb.
(c) The lithām is essentially the burquʿ, except that it sits on the tip of the nose, making its opening wider than that of the niqāb.

Benefit:
According to the well-known position in the school of Imām Aḥmad and others, the details of what constitutes ʿawrah during the prayer are as follows:

1. The ʿawrah of an adult man, of anyone who has reached ten years of age, and of a girl approaching puberty is the region between the navel and the knee.
2. The ʿawrah of a boy from seven to ten years old is limited to the two private parts alone.
3. The ʿawrah of a free, adult woman is her entire body except for her face; on the preponderant view of the scholars, the face is not ʿawrah in the prayer.