The Sahara (/səhɑːrə/, /səhærə/; Arabic: الصحراء الكبرى‎, 'the Greatest Desert') is a desert on the African continent. With an area of 9,200,000 square kilometres (3,600,000 sq mi), it is the largest hot desert in the world and the third largest desert overall, smaller only than the deserts of Antarctica and the northern Arctic. The name "Sahara" is derived from the Arabic word for "desert" in the feminine irregular form. 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.