A dead end is a street or path that doesn't go anywhere: it just stops. When you're riding your bike and hit a dead end, you have to turn around and find another route because there's no way through. Dead-end streets usually have signs warning drivers before they enter, and they often end with a circular turnaround.

The phrase also describes situations where you can't make any more progress. If you're working on a puzzle and realize the path you're following is a dead end, you need to backtrack and try a different approach. Scientists researching a cure might explore several ideas that turn out to be dead ends before finding one that works. A dead-end job is one without opportunities for advancement or growth: you might earn money, but you won't learn new skills or move up to better positions.

Running into dead ends is a normal part of solving problems and exploring. The key is recognizing when you've hit one so you can change direction. Thomas Edison famously tried thousands of materials before finding the right filament for the light bulb. Each failure was just another dead end on the path to success.