The Adim chord
The Adim (A - C - D#) is a diminished triad, which is why it sounds the ragtime piano grease. Writers pick it for a moment of unease, and you can find it across early jazz and the Great American Songbook. On guitar the chord sits naturally where most players already park their hand; on piano it stacks straight up under the right hand. The page below covers the voicings worth memorising, the theory, the progressions where the Adim earns its keep, and the records that lean on it.
Hear the Adim in the chord builder →Voicings for Adim
Common ways to grip the Adim on guitar and piano. Guitar diagrams read low E to high E left-to-right; an × means muted, an open circle above the nut means an open string. Filled dots are fretted notes.
Guitar , full chord shapes
CAGED-derived voicings for Adim across the neck. Pick the shape closest to where your hand already sits.
Guitar , triad shapes
Three-note triad shapes on each string set, shown moving up the neck. Light textures for arpeggios, pop layering and chord-melody work.
Piano voicings
Root position and inversions. The bass note matters: each inversion changes how the chord sits under a melody.
The theory behind Adim
Progressions that use Adim
Short progressions that put the Adim to work. Each one is shown in a different key so you can pick the one that suits your singer.
This chord appears as a borrowed or passing chord in many minor-key progressions.
→ Build this in the chord builderSongs that feature Adim
Real records where this chord does structural work. No lyrics quoted, just the title and artist so you can pull up a copy and hear it in context.
Related chords
Chords a step away from the Adim in the songwriting circle, the natural neighbours when you want a substitution.
Keys where Adim lives
The keys where this chord turns up diatonically. Open any key page for the full set of progressions that lean on it.
Related references
Other ways to put the Adim to work across the reference library.
More songwriting tools
Got the chord but still wrestling with the lyric? Find the right rhyme in RhymeForge, or break a writer's block with the unexpected word-pair generator in CollisionLab. Need to map a full progression? The chord builder on the home page is where the Adim fits into context. All free, no signup.
About the chord builder
The Undercover Zest chord progression builder is a free interactive tool that maps every diatonic and borrowed chord in every key. Click a Roman numeral to hear it, drag chords into a progression, then audition voicings, inversions and tensions until the song clicks.
This page is a static reference for the Adim. For interactive playback, voice-leading hints and substitution suggestions, open the chord builder above.