Outdoor area is completely level at the bottom of Georgian house, perhaps (6,4)

'the bottom of georgian house perhaps' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'outdoor area is completely level' is the wordplay.
I cannot quite understand how this works, but
'area' could be 'garden' (garden is a kind of area) and 'garden' is found within the answer.
'level' could be 'flat' (synonyms) and 'flat' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).

'at' is the link.

Can you help me to learn more?