Which of the following is NOT considered an ornament in music?

An ostinato is a musical phrase or rhythm that is persistently repeated, often in the same voice or instrumental part throughout a composition. Unlike ornaments, which are decorative melodic flourishes that embellish a primary melody without altering its essential nature, an ostinato serves as a foundational element or thematic material within a piece of music. It provides continuity and structure rather than embellishment, distinguishing it clearly from the other options listed, such as mordents, appoggiaturas, and turns, all of which serve to ornament or decorate a melody, enhancing its expressiveness.