Which musical term is used to describe a gradual increase in loudness?

The term used to describe a gradual increase in loudness is "crescendo." This term indicates a smooth, continuous buildup of volume in music, allowing the performer to create a sense of growing intensity or drama over a passage. It is often notated in sheet music with the word "crescendo" or by using the symbol " < " which visually represents the idea of sound swelling or building up.

In contrast, other musical terms listed have different meanings. "Decrescendo" refers to a gradual decrease in loudness, creating a softening effect rather than an increase. "Staccato" describes a style of playing where notes are sounded sharply and detached, which is unrelated to volume dynamics. Finally, "piano" denotes a soft volume level, indicating the opposite of an increase in loudness. Understanding these distinctions will help solidify the concept of dynamic markings in music.