What are keys that share the same tonic note called?

Keys that share the same tonic note are known as parallel major and minor keys. This concept is essential in understanding tonal music because it identifies two keys that have the same starting pitch but differ in their scale structure. For example, C major and C minor share C as their tonic note but have different sets of notes that create distinct sounds and emotional qualities.

In contrast, relative major and minor keys have different tonic notes, though they share the same key signature. Counterpoint refers to the relationship between two or more independent melodic lines. Chord progression involves the sequence of chords played in music, rather than a relation between keys. Understanding the distinction between parallel and relative keys is crucial for grasping the harmonic relationships that underpin much of Western music theory.