piano chord
A♭maj7
A♭1C3E♭5G7
Major triad with a major seventh: a half step below the root, an octave up.
Written the other way round it is G♯maj7 — the same twelve keys on a piano, a different piece of notation.
What is true of it
A♭maj7 is A♭, C, E♭ and G — 1, 3, 5 and 7 counted from A♭.
On an instrument that cannot reach all 4, the 5 goes first, in that order.