The crossword solution for the term KEY-RELATED is TONAL, which refers to the relationship between musical keys. Tonal music is based on a key center, or tonic, and the notes of the scale associated with it. This type of music is characterized by the use of chords and harmonic progressions that are based on the tonic. Tonal music is often contrasted with atonal music, which does not have a tonic or key center.