House in Palladian style
At Kedleston Hall the piano nobile is placed above a rusticated ground floor and reached by an external grand staircase. The upper floor windows indicate their lower status.
Source: Wikimedia Commons

A piano nobile, from the Italian meaning noble or grand floor, is the main floor of a Palladian or Georgian building. Containing the most important rooms, it is usually on the first floor above a basement or ground floor with another floor above it. It is often accessed by a grand exterior staircase.[1][2]

References

  1. p. 789
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Bibliography

Harman, Ruth, and Nikolaus Pevsner. Yorkshire West Riding: Sheffield and the South. 2017.
OED. “Piano Nobile.” Oxford English Dictionary, Online, Oxford University Press, 2018, http://www.oed.com/view/Entry/143295?redirectedFrom=piano+nobile#eid.