Gasteracantha (known as spiny-backed orb-weavers, spiny orb-weavers, or spiny spiders) is a genus of orb-weaver spiders first named by Carl Jakob Sundevall in 1833. The females of most species are brightly colored with six prominent spines on their broad, hardened, shell-like abdomens. The name Gasteracantha is derived from the Greek gaster (γαστήρ), meaning "belly, abdomen", and akantha (άκανθα), meaning "thorn, spine". Spiny-backed orb-weavers are sometimes colloquially called "crab spiders" because of their shape.