from The Century Dictionary.
- noun A bivalve mollusk of the family Petricolidæ.
Sorry, no etymologies found.
Soon after daybreak, Thirlwell, Drummond, and the rock-borer pushed their way through the woods behind the cliff.
He took the white rock-borer, but Agatha did not go with him.
She knew that Drummond and the rock-borer could do nothing with their claims except sell them to somebody who could supply the money to develop the mines; but before they started Thirlwell had outlined a plan by which the holdings might be consolidated and worked together.
The party broke up soon afterwards, and early next morning Agatha left the mine with Thirlwell, Drummond, and a white rock-borer as well as the half-breed packers.
Will you see what they're doing with that rock-borer? "