A dent is a small hollow or depression in a surface, usually caused by impact or pressure. When a baseball hits a car door, it might leave a dent: a pushed-in spot where the metal bent inward. You might find dents in aluminum cans, bicycle fenders, or even the side of a refrigerator where someone bumped it with a chair.

The word can also mean making progress on a difficult task. When you have a huge pile of homework and finally finish two assignments, you've made a dent in it. You haven't finished everything, but you've made visible progress. Similarly, if you're saving money for something expensive and you've saved your first twenty dollars, you've put a dent in the total amount you need.

Dents in metal or other materials can sometimes be popped back out, but deep dents might be permanent. That's why people get frustrated when their new bicycle gets its first dent: it's a mark that changes something from perfect to imperfect, even if it still works just fine.

As a verb, to dent means to make a dent in something.