What is acrachnid?

Arachnoid refers to a type of organism within the class Arachnida, which includes Spiders, scorpions, ticks, and mites. These creatures are characterized by having eight legs, a segmented body, and no antennae. They are primarily terrestrial and can be found in a variety of habitats. The term "arachnoid" can also refer to the arachnoid mater, one of the membranes that envelop the brain and spinal cord in the central nervous system.