diminuais

Diminuais is the Portuguese term used in music theory to describe diminished intervals and chords. The word comes from the adjective diminuto or diminuído, signaling a reduction in pitch distance relative to a standard major or perfect interval. In practice, a diminished interval is one semitone smaller than the corresponding major or perfect interval. For example, a diminished third spans two semitones, and a diminished fifth spans six semitones, one semitone smaller than a perfect fifth.

Diminuais also apply to chords. A diminished triad consists of a root, a minor third, and a diminished fifth (for example, C–E♭–G♭). A fully diminished seventh chord adds a diminished seventh above the root, resulting in a four-note chord built by stacking minor thirds (for example, C–E♭–G♭–B♭♭ in the conventional spelling). These chords are characterized by their tense, unresolved sound and are commonly used to create leading-tone motion back to a tonic chord.

Notation and analysis commonly denote diminished intervals and chords with the degree symbol (°) or the abbreviation dim in chord symbols. For instance, C° indicates a diminished triad, and C°7 indicates a fully diminished seventh chord. In functional harmony, diminuais serve as closely related sources of dissonance that resolve to more stable chords, often functioning as chromatic color or as passing harmonies.

Diminuais are a standard concept in Western tonal music found in classical, romantic, and jazz repertoires, where their precise spelling and voice-leading are important for preserving interval quality and harmonic function. See also diminished versus augmented intervals and chord qualities.