To widen means to make something broader or to become broader. When a river widens, it spreads out and becomes less narrow. When you widen your eyes in surprise, you open them bigger. A road crew might widen a highway by adding extra lanes so more cars can travel on it at once.

The word works both ways: something can widen on its own, or you can widen it yourself. A crack in a wall might slowly widen over time. But you might also deliberately widen a doorway during a renovation to make it easier to move furniture through.

You can widen things that aren't physical too. When you travel to new places or read books about different cultures, you widen your horizons, meaning you expand your understanding of the world. A teacher might help widen your perspective on a historical event by showing you viewpoints you hadn't considered. When a company widens its product line, it offers more variety to customers.

The opposite of widen is narrow. Think of it this way: widening always means more space, more breadth, or more possibilities, whether you're talking about a path through the woods or your knowledge of science.