Why does duration mean?

Duration means length of time something lasts, from Latin durare meaning to last, endure, or continue, and it is used to measure elapsed time from start to finish. The question why does duration mean is asking about its meaning and origin. Duration means how long an event, activity, or state continues, measured in time units like seconds, minutes, hours, days, months, or years. For example, duration of a movie is its runtime, duration of a job is how long it takes, duration of a warranty is how long coverage lasts. In roofing, Owens Corning Duration shingles name implies lasting performance. Duration means not just time but persistence, endurance, and continuity over time. It answers question how long. In physics, duration is interval between events. In finance, duration measures bond price sensitivity to interest rate changes, meaning how long it takes to recover investment. In project management, duration is time needed to complete task. So why does duration mean what it means, because language evolved from Latin durus meaning hard, lasting, with idea of something hard enduring over time, so duration came to mean lasting time. It means length, period, term, span, and is used to quantify time something exists or occurs, distinguishing from point in time. So duration means extent of time.