Diminished third

In <a href="/facts/Classical_music/oglVXmSb">classical music</a> from <a href="/facts/Western_culture/rPbgAhzI">Western culture</a>, a diminished third (Playⓘ) is the <a href="/facts/Interval_(music)/aFwkkgpY">musical interval</a> produced by <a href="/facts/Diminution/Ge60Hmo2">narrowing</a> a <a href="/facts/Minor_third/4y8zBxwY">minor third</a> by a <a href="/facts/Chromatic_semitone/9VT0YqGE">chromatic semitone</a>. For instance, the interval from A to C is a minor third, three semitones wide, and both the intervals from A♯ to C, and from A to C♭ are diminished thirds, two semitones wide. Being diminished, it is considered a <a href="/facts/Consonance_and_dissonance/RfQJwFFF">dissonant</a> interval.
In <a href="/facts/12-tone_equal_temperament/89BK2lpj">12-tone equal temperament</a> a diminished third is <a href="/facts/Enharmonic/lSwDb7JN">enharmonic</a> with the <a href="/facts/Major_second/x94d53Fo">major second</a>, both having a value of 200 <a href="/facts/Cent_(music)/lsm8TJgX">cents</a>. However, in <a href="/facts/Meantone_temperament/bVoQDGQs">meantone</a> tunings with fifths flatter than 700 cents, the diminished third is wider than the major second. In <a href="/facts/19_equal_temperament/RWw5bQLP">19 equal temperament</a> it is in fact enharmonically equivalent to an <a href="/facts/Augmented_second/nHnGftmV">augmented second</a>, both having a value of 252.6 cents. In 
<a href="/facts/31_equal_temperament/XfXmqNrR">31 equal temperament</a> it has a more typical value of 232.3 cents. In a twelve-note keyboard tuned in a meantone tuning from E♭ to G♯, the dimininished third appears between C♯ and E♭, and again between G♯ and B♭.
In superpythagorean tunings, the diminished third is narrower than the major second. In the special case of <a href="/facts/17_equal_temperament/84tJAs43">17 equal temperament</a>, the chromatic semitone and diminished third are in fact represented by the same interval of 141.18 cents, which allows the minor third to be evenly divided in half. In <a href="/facts/22_equal_temperament/p6XzgSwP">22 equal temperament</a>, the diminished third is ~ 109 cents while the chromatic semitone is ~ 163 cents and the diatonic semitone is ~ 55 cents.
In <a href="/facts/Septimal_meantone_temperament/ArDQnlkN">septimal meantone temperament</a> the diminished third is considered to approximate the interval of a <a href="/facts/Septimal_major_second/Ih7AfbPc">septimal major second</a> (playⓘ), with ratio 8/7, and in any meantone tuning in the vicinity of <a href="/facts/Quarter-comma_meantone/vKBhPmfs">quarter-comma meantone</a>, such as 31-equal temperament, it will come close to that value; for instance in 31-equal temperament the diminished third is a cent sharp of 8/7.
The <a href="/facts/Complement_(music)/R5NpcqlD">complementary interval</a> to the diminished third is the <a href="/facts/Augmented_sixth/Shp8yMJ5">augmented sixth</a>, and the numerous chords of <a href="/facts/Common_practice/nJ8HnoB2">common practice</a> music described as <a href="/facts/Augmented_sixth_chord/opQjhzUK">augmented sixth chords</a> thereby contain the diminished third as well. For example, a German sixth chord E♭-G-B♭-C♯-E♭' exhibits a diminished third between C♯ and E♭' which complements the augmented sixth between E♭ and C♯.
The just diminished third arises in the extended C major scale between F♯ and A♭, Playⓘ and between B and D♭.

Diminished third open-in-new

Diminished third