pitch class

A pitch class is a group of all musical notes that share the same letter name or sound "core," regardless of octave. For example, all C notes—whether high or low—belong to the same pitch class, often labeled as "C." This concept helps musicians organize and analyze music by focusing on the note's identity, ignoring its specific pitch height. Pitch classes are fundamental in music theory, especially in understanding scales, chords, and harmony, because they group notes by their fundamental sound, providing a simplified way to study and compare musical structures.