piano chord
Eadd9
E1G♯3B5F♯9
A major triad with a ninth added and no seventh — which is what tells it apart from a ninth chord.
What is true of it
Eadd9 is E, G♯, B and F♯ — 1, 3, 5 and 9 counted from E.
On an instrument that cannot reach all 4, the 5 goes first, in that order.