古典音樂的和弦記號是和調性(key)互相對應的。羅馬數目字代表和弦的根音(root)在那個調音階裏的位置。例如在C大調音階上,I, ii, iii, IV, V, vi viio相等於流行音樂的C, Dm, Em, F, G, Am, Bdim和弦。而在A小調,i, iio, III, iv, V, VI, viio相等於流行音樂的Am, Bdim, C, Dm, E, F, G#dim。
由四個音,按照三度關係疊置的,稱為七和弦。當七和弦中的四個音按三度排列時,最下方三個音的名稱與三和弦相同,分別為「根音」、「三音」、「五音」,而根音上方的七度音,即稱為「七音」。常用的七和弦,可分為五種:屬七和弦/大小七和弦(Dominant 7th/Major minor 7th)、大七和弦(Major 7th)、小七和弦(minor 7th)、半減七和弦(half-diminished 7th)、減七和弦(diminished 7th)。除上述五种常见的七和弦外,还有增七和弦(Augmented Major 7th)、小大七和弦(minor Major 7th)等其他类型的七和弦。
Grout, Donald Jay (1960). A History Of Western Music. Norton Publishing.
Dahlhaus, Carl. Gjerdingen, Robert O. trans. (1990). Studies in the Origin of Harmonic Tonality, p. 67. Princeton University Press. ISBN0-691-09135-8.
Goldman (1965). Cited in Nattiez (1990).
Jones, George T. (1994). HarperCollins College Outline Music Theory. ISBN0-06-467168-2.
Nattiez, Jean-Jacques (1990). Music and Discourse: Toward a Semiology of Music (Musicologie générale et sémiologue, 1987). Translated by Carolyn Abbate (1990). ISBN0-691-02714-5.
Norman Monath, Norman (1984). How To Play Popular Piano In 10 Easy Lessons. Fireside Books. ISBN0-671-53067-4.
Stanley Sadie and John Tyrrell, eds. (2001). The New Grove Dictionary of Music and Musicians. ISBN1-56159-239-0.
Surmani, Andrew (2004). Essentials of Music Theory: A Complete Self-Study Course for All Musicians. ISBN0-7390-3635-1.
延伸閱讀
Benward, Bruce & Saker, Marilyn (2002). Music in Theory and Practice, Volumes I & II (7th ed.). New York: McGraw Hill. ISBN0-07-294262-2.