A hiccup is a sudden, involuntary sound your body makes when your diaphragm (the muscle under your lungs that helps you breathe) spasms and causes you to gulp air quickly. The gulp gets cut off by your vocal cords snapping shut, creating that distinctive hic! sound. Hiccups usually come in a series, one after another, and can last anywhere from a few minutes to, in rare cases, much longer.

Nobody knows exactly why we get hiccups, though they often happen after eating too fast, drinking carbonated beverages, or getting excited. Most hiccups go away on their own, though people have invented countless remedies: holding your breath, drinking water upside down, or getting startled. Whether these actually work, or the hiccups were about to stop anyway, remains a mystery.

The word also describes a small problem or delay. If your science fair project hits a hiccup, you've encountered an unexpected complication. When someone says “it went off without a hiccup,” they mean everything went perfectly smoothly. These minor setbacks are like the physical hiccup: annoying and inconvenient, but usually temporary and not seriously harmful.