An Etymological Dictionary of Astronomy and Astrophysics

1. An arid land where average annual precipitation is so low (usually taken as below 250 mm mean annual rainfall) that it will not adequately support vegetation, and where the potential rate of evaporation far exceeds precipitation.
   

2. Any place lacking in something; → brown dwarf desert.

Etymology (EN): From M.E., from O.Fr. desert, from L.L. desertum, literally “thing abandoned,” from deserere “to abandon.”

Etymology (PE): Kavir “salt and sour ground, where nothing grows; wilderness,” of unknown origin.