chrōma, atis (atos, Vitr. 5, 5), n., = χρῶμα (a color), in music, a chromatic scale (a species of harmony in which the tones of the tetrachord measure two and a half tones, as a half, again a semitone, and then a tone and a half follow each other), Vitr. 5, 4, 3; cf. Dict. of Antiq. p. 645.

—Hence, chrōmaticē, ēs, f., the science of this species of harmony, Vitr. 5, 5; and: chrō-maticus, a, um, adj., chromatic: genus, the same, Macr. Somn. Scip. 2, 4 fin.