What is the definition of a scale in music?

A scale in music is defined as a sequence of notes that are arranged in a specific order, either ascending from a lower pitch to a higher pitch or descending from a higher pitch to a lower pitch. This concept forms the basis of melody and harmony and is crucial for understanding musical structure. Each scale typically contains a set number of notes, which can be determined by the scale type (e.g., major, minor, chromatic).

The other options do not accurately represent the concept of a scale. A single note played repeatedly does not encompass the idea of a sequence or progression of pitches. A harmonic chord involves a combination of notes played simultaneously rather than sequentially. Lastly, the speed of a piece of music, known as tempo, is unrelated to the concept of a scale itself. Therefore, the definition provided in the correct choice encapsulates the foundational role that scales play in music.