Explain the term "ostinato".

The term "ostinato" refers to a musical phrase or rhythm that is persistently repeated throughout a piece of music. This can create a sense of continuity and drive, often serving as a foundational element over which other musical lines are introduced. Ostinatos can appear in various forms across different genres, from classical compositions to modern popular music, establishing a framework that supports melodies or harmonies.

In contrast, the other options address different musical concepts. Dynamic contrast involves variations in loudness, which shapes the emotional impact but does not specifically relate to repetition. A series of chords in succession typically describes a chord progression, which may or may not include repetitions. Vocal ornamentation refers to decorative notes added to a melody to enhance expressiveness without emphasizing the repetitive aspects that characterize an ostinato. Therefore, understanding "ostinato" as a repeated musical phrase or rhythm highlights its unique role in creating structure and texture in music.