Really good friend's introduced Buckingham say (6)
I believe the answer is:
palace
'buckingham say' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'really good friend's introduced' is the wordplay.
I cannot really see how this works, but
'friend' could be 'pal' (pal can mean a friend) and 'pal' is found within the answer.
The remaining letters 'ace' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for palace that I've seen before include "Locality round a monarch's official residence" , "See 16" , "Home fit for a king" , "Royal house" , "See 10" .)