Tarantula n. : Any one of several species of large spiders, popularly supposed to be very venomous, especially the European species (Tarantula apuliae). The tarantulas of Texas and adjacent countries are large species of Mygale.

Example:
How can one tell a female Tarantula from a male Tarantula?

Taxonomy
tarantulas, species, spiders, urticating hairs, abdomen, legs, chelicerae, bites, prosoma, North American tarantulas, pet tarantulas, pedipalps, subfamily, new-world, venom, moult, Theraphosidae, females.

Defination from the web:
tarantula is an invertebrate that relies on an exoskeleton for muscular support. A tarantula's body consists of two main parts, the prosoma or the cephalothorax (the former is most often used) and the abdomen or opisthosoma. ...