What is the symbol of duration?

The symbol of duration is typically represented by the letter "D," which denotes the length of time an investment or financial instrument is expected to be held. In finance, duration measures the sensitivity of a bond's price to changes in interest rates, reflecting both the time until cash flows are received and the present value of those cash flows. In other contexts, such as music or film, duration refers to the length of time a note, sound, or scene is sustained.