You already know it's a Cmaj7. The question is how to play it. Every other piano chord app lights up four keys and stops. But four dots on a keyboard isn't the hard part — voicing the chord so it actually sounds good in your track is. Keytionary is built for that. Pick any chord. Hear every way to voice it: • Close, Open (drop-2), Drop 3, Drop 2 & 4 • Shell and rootless voicings (the jazz/neo-soul backbone) • Wide two-hand spreads and stacked-fourths quartal voicings • Upper-structure triads — the "triad over bass" trick And it answers the question every app ignores: what does your left hand do? Swap the foundation under any voicing — root, root + 5th, root + 10th, octaves — and hear it change instantly. Plus the full reference: 35 chord types, scales, diatonic and famous progressions, and a playable keyboard — all with real piano samples.