Which of the following terms refers specifically to a musical passage with embellished notes?

The term that specifically refers to a musical passage with embellished notes is "ornaments." Ornaments are decorative notes added to melody lines to embellish and enhance the music, such as trills, turns, mordents, and grace notes. They serve to add expressiveness and complexity to a piece, allowing performers to showcase their interpretive skills.

In contrast, ostinato refers to a repeated musical phrase or rhythm that persists throughout a piece, often in the bass line. An arpeggio is a technique in which the notes of a chord are played in succession rather than simultaneously, typically creating an upward or downward flowing sound. Enharmonic refers to notes that sound the same but are notated differently (for example, C# and Db), which is unrelated to embellishments within a melody. Each of these terms serves a specific purpose in music theory but does not pertain to the concept of added embellishment as ornaments do.