DOMINANT

in music, fifth tone of the diatonic scale (which has five whole tones and two semitones), e.g., G in the scale of C. In the tonality of Western music of the 17th to 19th century, the dominant was particularly important, for it stood in strongest relation to the tonic, or keynote (C in the key of C). Chords based on the dominant had a strong tendency to move to the tonic chord, and the key built upon the dominant was most strongly related to the tonic key. The relation between dominant and tonic was exploited in musical forms such as the sonata.