Tonality is a system of music in which certain hierarchical pitch relationships are based on a key "center" or tonic. The term tonalité originated with Alexandre Choron (1810) and was borrowed by François-Joseph Fétis in 1840 (Reti, 1958; Simms 1975, 119; Judd, 1998; Dahlhaus 1990). Although Fétis used it as a general term for a system of musical organization and spoke of types de tonalités rather than a single system, today the term is most often used to refer to Major-Minor tonality (also called diatonic tonality or functional tonality), the system of musical organization of the common practice period and most popular music in much of the world today.

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• [Tonality is] the special meaning [functions] that chords receive through their relationship to a fundamental sonority, the tonic triad.
  • Hugo Riemann, cited in Gurlitt, W. (1950). "Hugo Riemann (1849-1919)".

• [Tonality is the] set of relationships, simultaneous or successive, among the tones of the scale.
  • Joseph Fétis, (1722). Traité complet de la théorie et de la pratique de l'harmonie contenant la doctrine de la science et de l'art, 2d ed., p.166. Brussels and Paris.

• In the passage quoted here from Monteverdi's madrigal [Cruda amarilli, mm.9-19 and 24-30], one sees a tonality determined by the accord parfait [root position major chord] on the tonic, by the sixth chord assigned to the third and seventh degrees, by the optional choice of the accord parfait or the sixth chord on the sixth degree, and finally, by the accord parfait and, above all, by the unprepared seventh chord (with major third) on the dominant. (p.171)
  • Joseph Fétis, (1722). Traité complet de la théorie et de la pratique de l'harmonie contenant la doctrine de la science et de l'art, 2d ed., p.166. Brussels and Paris.

• For the elements of music, nature provides nothing but a multitude of tones differing in pitch, duration, and intensity by the greater or least degree... The conception of the relationships that exist among them is awakened in the intellect, and, by the action of sensitivity on the one hand, and will on the other, the mind coordinates the tones into different series, each of which corresponds to a particular class of emotions, sentiments, and ideas. Hence these series become various types of tonalities. (p.11f)
  • Joseph Fétis, (1722). Traité complet de la théorie et de la pratique de l'harmonie contenant la doctrine de la science et de l'art, 2d ed., p.166. Brussels and Paris.

• But one will say, 'What is the principal behind these scales, and what, if not acoustic phenomena and the laws of mathematics, has set the order of their tones?' I respond that this principle is purely metaphysical [anthropological]. We conceive this order and the melodic and harmonic phenomena that spring from it out of our conformation and education. (p.249)
  • Hugo Riemann, cited in Gurlitt, W. (1950). "Hugo Riemann (1849-1919)".

• [Tonality is] the art of combining tones in such successions and such harmonies or successions of harmonies, that the relation of all events to a fundamental tone is made possible.
  • Arnold Schoenberg (1937). Schoenberg, p.280, ed. Armitage, Merle. New York.

• Tonality is the organized relationship of musical sounds, as perceived and interpreted with respect to some central point of reference that seems to co-ordinate the separate items and events and to lend them meaning as component parts of a unified whole.
  • Delbert M. Beswick (1950). The Problem of Tonality in Seventeenth Century Music, p.18, Ph.D. dissertation. University of North Carolina.

• [Tonality is] prolonged motion within the framework of a single key-determined progression.
  • Salzer, Felix (1962). Structural Hearing: Tonal Coherence in Music. New York: Dover, p.227.

• [Tonality is] contrapuntal progressions ... can be key defining and capable of assuming structural significance.
  • Salzer, Felix (1962). Structural Hearing: Tonal Coherence in Music. New York: Dover, p.204.

• [Tonality is] directed motion within the framework of a single prolonged sonority.
  • Salzer, Felix (1967). "Tonality in Medieval Polyphony", The Music Forum 1, p.54.

• The inception of the principle of tonality and certain of its techniques expressing themselves in the construction of tonal units of various length and complexity goes as far back as the Organa of St. Martial and Santiago de Compostela. A continuous development of structural polyphony from the twelfth to the twentieth century may with justification be assumed. Whether we encounter the use of modes or the major-minor system, whether the contrapuntal voice voice leadings are different from those of later periods or whether harmonic thinking expresses itself in a different manner than later on in the eighteenth century, the music of the Middle Ages and Renaissance demonstrates the same basic principles of direction, continuity and coherence as music from the Baroque period to the twentieth century.
  • Salzer, Felix (1962). Structural Hearing: Tonal Coherence in Music, p.281. New York: Dover.

• "Music is tonal when its motion unfolds through time a particular tone, interval, or chord."
  • Roy Travis (1959). "Toward a New Concept of Tonality", Journal of Music Theory 3, p.261.

• "The medieval musician ... did not hear a triad as a triad ... a textbook definition of tonal coherence is not the same as the phenomenon of tonal cognition as experiences."
  • Richard Norton (1984). Tonality in Western Culture, p.125. University Park and London: The Pennsylvania State University Press.