Factor (chord)In music, a factor or chord factor is a member or component of a chord. These are named root, third, fifth, sixth, seventh, ninth (compound 2nd), eleventh (compound 4th), thirteenth (compound 6th), and so on, for their generic interval above the root. In harmony, the consonance and dissonance of a chord factor and a nonchord tone are distinguished, respectively. Chord factors are taken into consideration in voicing and voice leading.
Dyad (music)In music, a dyad (less commonly, diad) is a set of two notes or pitches that, in particular contexts, may imply a chord. Dyads can be classified by the interval between the notes. For example, the interval between C and E is a major third, which can imply a C major chord, made up of the notes C, E and G. When the pitches of a dyad occur in succession, they form a melodic interval. When they occur simultaneously, they form a harmonic interval. The harmonic series is built over a fundamental pitch, and the rest of the partials in the series are called overtones.
Primary triadIn music, a primary triad is one of the three triads, or three-note chords built from major or minor thirds, most important in tonal and diatonic music, as opposed to an auxiliary triad or secondary triad. Each triad found in a diatonic key corresponds to a particular diatonic function. Functional harmony tends to rely heavily on the primary triads: triads built on the tonic, subdominant, and dominant degrees. The roots of these triads begin on the first, fourth, and fifth degrees (respectively) of the diatonic scale, otherwise symbolized: I, IV, and V (again, respectively).
