👉 An undrilled term is a term that has been drilled into, or has been drilled through, an existing surface. This process involves using a drill to dig holes into the ground and then inserting a string of steel rods into the hole to create a tunnel or pipe. The term "undrillable" refers to the fact that the steel rods are not anchored to the ground, which means they can easily be pulled out from under the earth.
