What spider family is commonly called orb-weavers?

The spider family commonly called orb-weavers is Araneidae.

Araneidae contains the familiar builders of spiral, wheel-shaped webs found in gardens, fields, and forests. The English word “orb” means circular, describing the web’s characteristic outline. These spiders are among the most recognizable web-building arachnids, and many species have bright colors, patterned abdomens, or spiny legs.

Araneid web construction usually begins with a framework of nonsticky silk. The spider then adds radiating supports and a spiral capture thread coated with sticky droplets. Flying or jumping insects that strike the web can become trapped, allowing the spider to detect vibrations and attack.

Araneidae is a cosmopolitan family with almost 5,000 described species in about 200 genera. The name orb-weaver can sometimes be used more broadly because other families, including Tetragnathidae and Uloboridae, also build orb-like webs. That broader usage is why Araneidae is the canonical answer for the family question, but not every orb-shaped web belongs to an araneid.