Ground plan (4)
I believe the answer is:
plot
'ground plan' is the definition.
(thesaurus)
'ground' is the wordplay.
I cannot quite understand how this works, but
'ground' could be 'lot' (I've seen this in another clue) and 'lot' is present in the answer.
A single letter 'p' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for plot that I've seen before include "Gunpowder, for one" , "The story told in a novel" , "Scheme; graph" , "Story or piece of land" , "Small piece of ground" .)