Durations are periods of time that can be measured and quantified. Timeframes, spans, TERMS, and lengths are all words used to describe durations. Timeframes are 10 letter words that refer to a period of time in which something is expected to happen or be completed. Spans are 5 letter words that refer to the amount of time something lasts or continues. TERMS are also 5 letter words that refer to a period of time during which something is in effect. Lastly, lengths are 7 letter words that refer to the amount of time something takes up.