Spider taxonomy is the part of taxonomy that is concerned with the science of naming, defining and classifying all spiders, members of the order Araneae of the arthropod class Arachnida, which has more than 53,000 described species. However, there are likely many species that have escaped the human eye as well as specimens stored in collections waiting to be described and classified. It is estimated that only one-third to one half of the total number of existing species have been described.