Which term describes the gradual increase in loudness?

The term that describes the gradual increase in loudness is "crescendo." A crescendo is a musical directive indicating that the sound is to be played with increasing intensity and volume over a period of time. This technique is commonly used in music to create a sense of build-up or rising tension, enhancing the overall emotional impact of a piece.

In contrast, "decrescendo" refers to a gradual decrease in loudness, which is the opposite of crescendo. "Forte" indicates a loud volume but does not imply a change or gradual increase over time. "Staccato" describes a playing style where notes are played sharply and separated, rather than focusing on volume dynamics. Understanding these terms is essential for interpreting music direction and dynamics effectively.