Three single-frequency tones or sounds sounded sequentially.
A chord composed of a fundamental tone and a third and fifth above.
(1) A chord of three notes.
(2) A common chord. Triads are said to be major, minor, augmented, and diminished. (Stainer, John; Barrett, W.A.; A Dictionary of Musical Terms; Novello, Ewer and Co., London, pre-1900)
[Major/Major Triads] - C E G# - D F# Bb — E G# C - G# C E (Augmented triads)
[Major/Minor Triads] C E G - F A C - G B D - D F# A (Major triads)
[Minor/Major Triads] C Eb G - D F A - C# E G# - A C E (Minor triads)
[Major/Minor Triads] C E G as above
[Minor/Major Triads] as above
[Minor/Minor Triads] - B D F - C Eb F#- F# A C - Eb Gb A (Diminished triads)
The material of which music is made is tone, in recognizable, orderly chord groups. The simplest chord group is the Triad, or three tone chord. (Also called Fifth, where two thirds makes a Fifth). The Triad always consists of fundamental (root), third and fifth. A Triad may be constructed upon every degree of the scale, Major and Minor. Upon the Major Scale tones the Triads of the key, in C Major, are shown above. These seven Triads occur in exactly the same form in every Major Key. There are three different Triad groupings in the above:
Major Triad: Major Third and Perfect Fifth on the 1st, 4th and 5th degrees.
Minor Triad: Minor Third and Perfect Fifth on the 2nd, 3rd and 6th degrees.
Diminished Triad: Minor Third and Diminished Fifth on the 7th degree.
Passage from Coleridge, The Friend: "EVERY POWER IN NATURE AND IN SPIRIT must evolve an opposite, as the sole means and condition of its manifestation: AND ALL OPPOSITION IS A TENDENCY TO RE-UNION. This is the universal Law of Polarity or essential Dualism... The Principle may be thus expressed. The Identity of Thesis and Antithesis is the substance of all Being; their Opposition the condition of all Existence, or Being manifested; and every Thing or Phenomenon is the Exponent of a Synthesis as long as the opposite energies are retained in that Synthesis."
Hamilton notes on the above passage: "So far as I understand this principle, I would perhaps express it thus:- Power can be manifested only by its effects, that is, by overcoming Resistance, which is Contrary Power. Existence is manifested by the struggle between two opposite tendencies ... Each particular phenomenon, or individual Manifestation of Existence, is determined to be such as it is, and no other, by the kind and degree of its producing Power, that is, by its own particular combination or synthesis of two opposite tendencies. The thought of Being or Existence general (a new name, the property of which may demand a special inquiry), as distinquished from phenomena, that is, from individual manifestations of existence, arises in us along with, and as a realization or externalization of, our belief in a common ground, a hidden principle of unity, belonging to the two opposite tendencies." (Hankins, Thomas L.; Sir William Rowan Hamilton; The John Hopkins University Press)