An arid expanse is a large area of land that is dry and barren due to lack of rainfall. The SAHARA, a 6 letter word, is the world's largest DESERT, covering much of North Africa. The DESERT, also a 6 letter word, is a type of arid climate in which there is very little rainfall. The Gobi, a 4 letter word, is a DESERT located in northern China and southern Mongolia. The SAHARAN, a 7 letter word, is an adjective used to describe something related to the SAHARA DESERT.