What musical term refers to notes being held longer than their typical value?

The term that refers to notes being held longer than their typical value is "sostenuto." This term indicates a style of playing that emphasizes sustaining notes, allowing them to resonate more fully and giving the performer the freedom to create a more lyrical and expressive sound. In practical application, sostenuto can be used in various contexts, such as a thematic passage where a melody is meant to linger and convey emotion, or in contrasting sections where a sustained note can provide depth against more rhythmically driven music.

The other terms have distinct meanings that do not convey the same idea. "Staccato" refers to notes played sharply and with a break between them, creating a clipped or separated effect. "Legato" indicates a smooth and connected style of playing, where notes are performed in a flowing manner without choppiness. "Piano" denotes a dynamic level, specifically playing softly, and does not pertain to the duration of notes directly. Thus, sostenuto is the term that accurately captures the concept of elongating the duration of notes beyond their standard values.