A more thorough explanation:

Definition: Duration refers to the length of time that something lasts or continues.

For example, the duration of a movie is the length of time it takes to watch the entire film. The duration of a class is the length of time that the class meets. The duration of a song is the length of time that the song plays.

Duration can also refer to the length of time that a property interest lasts, such as the duration of a lease or the duration of a mortgage. In addition, it can refer to the length of time that a trust exists.

Overall, duration is a measure of time and how long something lasts or continues.