Which term means "little by little"?

The term that means "little by little" is "poco a poco." In musical terminology, this phrase indicates a gradual change, typically in dynamics or tempo, suggesting that something should be done slowly and incrementally rather than all at once. In the context of music performance, this approach allows musicians to build intensity or complexity progressively, which can create a more nuanced and expressive interpretation of a piece.

"Poco," while also meaning "little," does not convey the same gradual sense without the additional "a poco." "Pianissimo" refers to a very soft dynamic level, and "prestissimo" indicates a very fast tempo. Therefore, "poco a poco" stands out uniquely as the term that encapsulates the concept of gradual progression, making it the correct choice for this question.