chro·mat·i·cism \ ̷ ̷ˈ ̷ ̷əˌsizəm\noun (-s) 1.: the quality or state of being chromatic 2. a.: the act or action of chromaticizing : the use of chromatic notes or tones < excessive chromaticism means excessive increase in harmonic tension — Mosco Carner > — contrasted with diatonicism b.: an instance of this use