Just a point of detail...the 'frame' as it is called in UK...or 'plate' as it is sometimes called on this side of the pond is sometimes referred to as the 'harp'....for obvious reasons...
The term is commonly used in piano dealerships and amongst technicians.

They often make for a good yacht mooring, but can break if dropped...

:-)

Peter Sumner
Piano technician
Redwood City
California