Meaning of rock bolt

rock' bolt"

Pronunciation: [key]
— Mining, Civ. Engin. Mining,Civ. Engin.
  1. a steel or fiberglass bolt inserted and anchored in a hole drilled in rock to prevent caving of the roof of a tunnel or subterranean chamber.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.