The word bore has several meanings:

1. To make someone feel tired and uninterested through dullness or repetition. A movie with a slow, predictable plot might bore its audience. A long speech filled with facts you already know can bore you, making minutes feel like hours. When something bores you, your attention drifts and you struggle to stay focused. A person who talks endlessly about the same topic might become a bore, someone others avoid at parties. The feeling itself is called boredom.
2. To drill or dig a hole through something. Workers bore tunnels through mountains for trains to pass through. A carpenter might bore holes in wood with a drill bit. Termites bore through timber, creating networks of tunnels. Scientists studying ancient ice bore deep into glaciers to extract long columns called ice cores. The channel created is also called a bore: “The dentist's drill made a small bore in the tooth.”
3. The inside diameter of a tube or gun barrel. A rifle's bore is the width of the space inside its barrel. Engineers measure the bore of pipes and cylinders precisely because it affects how fluids or gases flow through them.