What is "toggle bolt"

n. A fastening device consisting of a bolt and a pair of hinged, usually sprung, wings threaded at the hinge to receive the bolt, used by inserting the bolt with wings folded into a small hole in a sheet material to the point where the wings unfold and the bolt can be tightened.

n. a fastener consisting of a threaded bolt and a hinged spring-loaded toggle; used to fasten objects to hollow walls

A toggle bolt, also known as a butterfly anchor, is a fastener for hanging things on hollow walls such as drywall.

Toggle bolts have wings that open inside a hollow wall, bracing against it to hold the fastener securely.

The wings are much larger than the bolt they are attached to. This spreads the weight of the secured item over a larger area, increasing the weight that can be secured compared to a regular bolt.