piano chord
B♭
B♭1D3F5
A major third and a perfect fifth over the root.
Written the other way round it is A♯ — the same twelve keys on a piano, a different piece of notation.
What is true of it
B♭ is B♭, D and F — 1, 3 and 5 counted from B♭.
On an instrument that cannot reach all 3, the 5 goes first, in that order.