What are passing notes in music?

Passing notes are indeed characterized as unessential notes that connect chord tones and are not part of the underlying harmony. Their primary role is to smoothly connect two notes of a chord by stepwise motion, thus adding movement and interest to a melodic line.

These notes typically fill the gaps between essential tones, enriching the melody without forming part of the harmonic foundation. For example, if a melody moves from a chord tone to another chord tone, a passing note can be inserted between them to create a smoother melodic transition. This technique is common in various musical styles and helps to enhance the expressiveness of a piece.

In contrast, essential notes that form the melody focus more on the primary thematic material, while notes that create a dramatic effect or signify a key change serve different compositional purposes. These latter options address aspects of musical structure and emotional impact rather than the specific function of passing notes in connecting melodic lines.