A setback is an event that stops your progress or pushes you backward, at least temporarily. When a basketball team loses their star player to an injury right before the championship, that's a major setback for their season. When you're building a treehouse and a storm destroys half your work, you've experienced a setback.

The word captures something important about progress: it rarely moves in a straight line. Scientists pursuing a cure for a disease face setbacks when experiments fail. An entrepreneur opening a restaurant might face setbacks from construction delays or equipment problems. A student working to improve their grades might suffer a setback from a surprisingly difficult test.

What matters most about setbacks is how people respond to them. Some people let a single setback convince them to quit entirely. Others treat setbacks as temporary obstacles, adjust their approach, and keep moving forward. Great achievements in history usually involved overcoming multiple setbacks along the way. Thomas Edison faced thousands of setbacks before successfully inventing a practical light bulb, and he famously said each failure taught him something valuable about what wouldn't work.