Why is antarctica considered as the biggest desert

Why is antarctica considered as the biggest desert?

By definition, a 'desert' is not decided by its temperature. A desert is a region that is simply very dry because its receives little to no water. To be considered a desert, an area must receive than 250 millimeters of annual precipitation. That's why it's easy for us to associate desert with 'hot, sandy areas' such as Sahara in Africa or Gobi in China.
The Antarctic Desert is the largest desert on Earth (13.8 million square kilometers). It is the coldest, windiest, and most isolated continent on Earth, and is considered a desert because its annual precipitation can be less than 51 mm.
Only 2% of Antarctica isn’t covered by ice, and this land is strictly along the coasts, where all the life that is associated with the land mass (i.e. penguins, seals and various species of birds) reside.
The other 98% of Antarctica is covered by ice which averages 1.6 km in thickness.