piano chord
A♭7
A♭1C3E♭5G♭♭7
Major triad, minor seventh. The chord that wants to resolve a fourth up.
Written the other way round it is G♯7 — the same twelve keys on a piano, a different piece of notation.
What is true of it
A♭7 is A♭, C, E♭ and G♭ — 1, 3, 5 and b7 counted from A♭.
On an instrument that cannot reach all 4, the 5 goes first, in that order.