expansion bolt

noun, Building Trades.
1.
a bolt inserted into a hole drilled in masonry and mechanically expanded to serve as an anchor for shelves, timbers, etc.
Examples from the web for expansion bolt
  • expansion bolt members to concrete unless shown otherwise.
  • Provide stainless steel expansion bolt fasteners as detailed.
  • Use toothed steel or expansion bolt devices for drilled in place anchors.
British Dictionary definitions for expansion bolt

expansion bolt

noun
1.
a bolt that expands on tightening, enabling it to be secured into an unthreaded hole