Tonality refers to the system or style of music that uses a specific key, with its corresponding tonic note and chord progression. It is often associated with classical Western music, where there is a clear sense of tonality in terms of major and minor keys, and harmony follows certain rules based on these keys. In contrast, atonal music does not follow any particular key or scale, and instead relies on individual pitches to create dissonance and consonance without the use of traditional chord progressions.