Duration is the length of time that something lasts or continues. When your teacher announces the duration of recess, she's telling you how many minutes you'll have to play outside. A movie's duration might be two hours, while a lightning flash has a duration of only a fraction of a second.

The word helps us talk precisely about how long events, conditions, or states persist. A doctor might ask about the duration of your headache: did it last ten minutes or all day? Scientists measure the duration of experiments. Athletes time the duration of their workouts.

Notice that duration focuses on the span itself, not when something starts or ends. If you ask, “What's the duration of summer vacation?” you're asking how long it lasts, not what date it begins. You might say, “We hiked for the duration of the afternoon,” meaning you hiked the whole time, from start to finish.

When something has a long duration, it sticks around. When it has a short duration, it passes quickly. Understanding duration helps you plan your time, manage expectations, and describe experiences accurately.