Consonance (English)

(1) A musical note that is in a harmonious relationship with another musical note (consonant interval). (2) A chord that is in harmony, i.e., synonymous with a consonant chord. Either way, it is closely related to the concept of harmony or a consonant interval. In contrast to a consonant interval, an interval relationship that does not resonate in harmony is called a dissonant interval, but interval relationships are always either consonant or dissonant, and the oppositional relationship between consonance and dissonance is also two sides of the same coin.

Consonance and dissonance were particularly actively discussed in Western music from the 17th century onwards. In that context, the most harmonious intervals were considered to be the relationships of 1st, 8th, 5th and 4th (perfect consonance intervals), the relationships of major and minor thirds and sixths were considered to be harmonious intervals (imperfect consonance intervals), and the relationships of major and minor second and seventh, as well as any relationships of augmentation and diminution, were considered to be dissonant intervals. In addition, when it comes to chords, those that are composed only of consonant intervals were called consonant chords, and those that contain dissonant intervals were called dissonant chords.

However, the concept of consonance and dissonance is created by human senses, and it has various different aspects depending on the era and the ethnic group. For example, in the same Western world, thirds and sixths, which are considered to be unshakable consonant intervals in modern times, were treated as dissonances before the 13th century. Furthermore, in modern music theory, the division of consonance and dissonance itself has lost its meaning, and the concept is used only as a convenient name.

[Toshiaki Kurosaka]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

(1)ある一つの楽音に対し、よく調和して鳴り響く音程関係（協和音程）にある楽音。(2)協和する和音、すなわち協和和音と同義。いずれにしても、協和の概念、あるいは協和音程と密接な関係がある。この協和音程に対して、調和して鳴り響かない音程関係を不協和音程というが、音程関係はかならず協和か不協和かのどちらかに含まれるのであり、協和と不協和の対立関係は、同時に表裏一体の関係をもなしている。

　この協和―不協和については、17世紀以降の西洋音楽でとくに活発に論ぜられた。そこでは、1度、8度、5度、4度の関係がもっともよく調和する音程（完全協和音程）、長短の3度と6度の関係がいちおう調和する音程（不完全協和音程）、長短の2度と7度、それにあらゆる増と減の関係が調和しない音程（不協和音程）とされた。また和音に対しても、協和音程だけで構成されているものを協和和音とよび、不協和音程を含むものを不協和和音とよんだ。

　ただし、協和―不協和の観念は、人間の感覚によって生ずるものであり、時代によって、また民族によっても、さまざまな異なる様相を呈している。たとえば、同じ西洋において、近代では揺るぎない協和音程とされている3度や6度も、13世紀以前は不協和音として取り扱われていた。さらに現代の音楽理論では、協和―不協和の区分そのものが意味をもたなくなり、その概念は便宜上の名称として使用されているにすぎない。

［黒坂俊昭］

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