Flooring material in centre of oblong houses (4)
I believe the answer is:
lino
'flooring material' is the definition.
'lino' can be an answer for 'material' (lino is a kind of material). I'm not certain of the 'flooring' bit.
'in centre of oblong houses' is the wordplay.
'centre of' indicates the central letters.
'houses' means one lot of letters goes inside another.
The middle letters of 'oblong' are 'lo'.
'in' placed into 'lo' is 'LINO'.
Can you help me to learn more?
(Other definitions for lino that I've seen before include "Floor covering (abbr)" , "put this down?" , "'Floor covering, in short (4)'" , "Tough floor covering" .)