Which word is closest to duration?

The word closest to duration is length, as both mean extent of time something lasts, with other close synonyms including period, span, term, time, and interval. Duration means length of time something continues, so length is closest because it directly measures extent, as in length of meeting is 2 hours. Period is also very close, meaning interval of time, such as trial period is 3 months. Span is close, meaning stretch of time, such as lifespan. Term is close, meaning fixed duration, such as term of contract is 5 years. Time is broader but close. In thesaurus, closest synonyms for duration are length, period, span, term, time, interval, stretch, extent, and continuation. For example, duration of movie could be called length of movie, runtime, or period. In roofing, Owens Corning Duration shingles brand uses Duration to imply long length of performance. In project management, duration is often called time span or elapsed time. Among all, length is most direct synonym because duration measures temporal length just as length measures spatial length. If you say what is duration, you can say what is length of time. So closest word is length, followed by period and span. Other close words include timeframe, interval, and stretch. So answer is length is closest word to duration, with period and span also very close, all conveying idea of how long something lasts.