Stones initially destined for flooring (6)
I believe the answer is:
screed
'flooring' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'stones initially destined' is the wordplay.
'stones' becomes 'scree' (scree is a mass of loose rocks on a mountain).
'initially' suggests taking the first letters.
The initial letter of 'destined' is 'd'.
'scree'+'d'='SCREED'
'for' is the link.
Can you help me to learn more?
(Other definitions for screed that I've seen before include "lengthy document" , "Long speech made by Saint Faith?" , "Lengthy statement" , "extensive text" , "A long written effusion" .)