under-pinning[ uhn-der-pin-ing ]SEE DEFINITION OF under-pinning
EXAMPLES FROM THE WEB FOR UNDER-PINNING
The shaft subsequently made on the Wapping shore was sunk to its full depth without any under-pinning.
He said it was a job for giants; clinging to the face of the precipice while you blew out and built on—under-pinning, isn't it?
And now he struck away the under-pinning of a few of the supports, so that the wagons could not be launched upon him by hand.