—v.t. 1. to pierce (a solid substance) with some rotary cutting instrument.
2. to make (a hole) by drilling with such an instrument.
3. to form, make, or construct (a tunnel, mine, well, passage, etc.) by hollowing out, cutting through, or removing a core of material: to bore a tunnel through the Alps; to bore an oil well 3000 feet deep. 4. Mach.to enlarge (a hole) to a precise diameter with a cutting tool within the hole, by rotating either the tool or the work.
5. to force (an opening), as through a crowd, by persistent forward thrusting (usually fol. by through or into); to force or make (a passage).
—v.i. 1. to make a hole in a solid substance with a rotary cutting instrument.
2. Mach. to enlarge a hole to a precise diameter.
3. (of a substance) to admit of being bored: Certain types of steel do not bore well.
—n. 1. a hole made or enlarged by boring.
2. the inside diameter of a hole, tube, or hollow cylindrical object or device, such as a bushing or bearing, engine cylinder, or barrel of a gun.