Arthropods
Invertebrates with segmented bodies and jointed appendages, members of the phylum Arthropoda including spiders, insects, and crustaceans.
 
Arachnids
Member of the class Arachnida in the phylum Arthropoda. Members have no antennae, a body divided into two regions, of which the first has four pairs of legs. Includes spiders, scorpions, ticks and mites.
 
Insects
Member of the class Insecta in the phylum Arthropoda. Members have three body regions and three pairs of legs.
 
Invertebrate
Animal that does not have an internal backbone.
 
Exoskeleton
External skeleton that protects the internal organs.

Prosoma (also called Cephalothorax)
The anterior region of an arachnid, a combination of the head and thorax.

Abdomen (also called Opisthoma)
The posterior region of an arachnid, contains most of the internal organs.

Pedicel
The narrow stalk of body that joins the prosoma and the abdomen.
 
Appendage
A limb or other part coming off the main body.

Pedipalps
A pair of modified appendages near the mouth that have a special function such as sensory or for grasping.

Chelicerae
A pair of modified appendages, usually specialized as fangs.

Spinnerets
The silk-releasing organs on a spider.
 
Carnivorous
Subsisting or feeding on animals.

Pre-Digestion
The process by which a spider eats, spitting up digestive juices onto prey so it begins to break down before it enters the spider's mouth.
 
Retreat
Hiding place for spiders who do not live in webs.

Orb Webs
Most commonly depicted type of spider web: concentric spirals along a spoked frame.

Egg Case
Silk sac created by female spiders to protect their eggs.
 
Spiderlings
Spiders that have just hatched.
 
Ballooning
Process where the wind which catches silk filaments attached to spiderlings and floats them away from each other and disperses them over a large territory.