To dwell means to live somewhere or to make a place your home. People dwell in houses, apartments, caves, or castles. Animals dwell in forests, oceans, or deserts. The word has an old-fashioned, almost poetic quality to it. You might read in a fairy tale about a wizard who dwells in a tower, or learn in science class about creatures that dwell in the deepest parts of the ocean.

The word also means to think about something for a long time, often too long. When you dwell on a mistake you made, you keep replaying it in your mind instead of moving forward. If you miss a question on a quiz and spend the whole afternoon thinking about it, you're dwelling on it. People might say not to dwell on past disappointments because it can keep you stuck in one moment instead of learning and growing.

A dwelling is a place where someone lives. A dweller is someone who lives in a particular place: a city dweller lives in a city, while a cave dweller lives in a cave.