Bores

Bores is a term with several related meanings in engineering, geology, and everyday language. As a noun, bore most commonly denotes the inner diameter of a hollow cylindrical object, such as a pipe or engine cylinder. The bore determines the cross‑sectional area of the cavity and affects performance; for example, an engine’s bore, together with its stroke, helps define displacement. In firearms, the bore refers to the interior of the gun barrel, and the caliber is a measure of this diameter.

As a verb, to bore means to make a hole through matter by drilling or to create a cylindrical passage, typically with a drill or boring machine. A hole produced in this way is called a borehole when it is drilled into rock, soil, or other formations. In mining and oil exploration, boreholes are drilled to access resources, sample formations, or install instruments.

In construction, woodworking, and metalworking, borer tools include drill bits and boring heads; following boring, reamers may be used to enlarge or finish a hole to precise dimensions and tolerances.

In everyday language, bore also describes a person who is dull or tiresome, and the verb to bore can mean to cause tedium or weariness. The word originates from Old English and Proto-Germanic roots related to piercing and drilling.