Dissonance has several meanings, all related to conflict or incongruity.

In music, dissonance is a property of an interval or chord. See consonance and dissonance. Wikibooks Wikiversity has more about this subject: School of Music Look up Music in Wiktionary, the free dictionary Wikisource, as part of the 1911 Encyclopedia Wikiproject, has original text related to this article: Music Meta has a page about this at: Music markup MusicNovatory: the science of music encyclopedia The... In music theory, an interval is the relationship between two notes or pitches, the lower and higher members of the interval. ... In music and music theory, a chord (from the Middle English cord) short for accord is two or more different notes or pitches sounding simultaneously, or nearly simultaneously, over a period of time. ... In music, a consonance (Latin consonare, sounding together) is a harmony, chord, or interval considered stable, as opposed to a dissonance, which is considered unstable. ...

In poetry, dissonance is the deliberate avoidance of patterns of repeated vowel sounds (see assonance). In general, words that are difficult to pronounce or contain harsh, rasping consonants are considered dissonant. Dissonance in poetry is similar to cacophony and the opposite of euphony. Poetry (ancient Greek: ποιεω (poieo) = I create) is traditionally a written art form (although there is also an ancient and modern poetry which relies mainly upon oral or pictorial representations) in which human language is used for its aesthetic qualities in addition to, or instead of, its notional and semantic content. ... SO LOOPY Assonance is the repetition of vowel sounds within a short passage of verse or prose. ... The band Cacophony Cacophony - Sounding badly, antonym to harmony. ... Euphony describes flowing and aesthetically pleasing speech. ...

Cognitive dissonance is a state of mental conflict. Cognitive dissonance is a condition first proposed by the psychologist Leon Festinger in 1956, relating to his hypothesis of cognitive consistency. ...