<P> The desert comprises much of North Africa, excluding the fertile region on the Mediterranean Sea coast, the Atlas Mountains of the Maghreb, and the Nile Valley in Egypt and Sudan . It stretches from the Red Sea in the east and the Mediterranean in the north to the Atlantic Ocean in the west, where the landscape gradually changes from desert to coastal plains . To the south, it is bounded by the Sahel, a belt of semi-arid tropical savanna around the Niger River valley and the Sudan Region of Sub-Saharan Africa . </P> <P> The Sahara can be divided into several regions including: the western Sahara, the central Ahaggar Mountains, the Tibesti Mountains, the Aïr Mountains, the Ténéré desert, and the Libyan Desert . </P> <P> The name' Sahara' is derived from ṣaḥārá (‏ صحارى ‎, pronounced / ˈsʕaħaːraː /), the plural of the Arabic word for "desert". </P> <P> The Sahara covers large parts of Algeria, Chad, Egypt, Libya, Mali, Mauritania, Niger, Western Sahara, Sudan and Tunisia . It covers 9 million square kilometres (3,500,000 sq mi), amounting to 31% of Africa . If all areas with a mean annual precipitation of less than 250 mm were included, the Sahara would be 11 million square kilometres (4,200,000 sq mi). It is one of three distinct physiographic provinces of the African massive physiographic division . </P>

What does the word sahara mean in arabic