Adult size ranging from 0.3 mm to 300 mm. They are arachnids with 4 pairs of legs and eye, some with 3 pairs of eye.
Some live solitarily, only converging to reproduce. Some species live in large communal webs, or congregate in large numbers under conducive environments. While some actively hunting for food while others lie in wait for prey to come in.
Their habitats comprises woodlands, forests, wetlands, grasslands, deserts, rainforests, trees, shrub, ground, tunnel underground to houses, farms, barns, gardens, attics, basements, foundations, and etc. People who fear of spider are known as Arachnophobia.