Focus delivered a calmness, did you say? (11)
I believe the answer is:
centrepiece
'focus' is the definition.
(I've seen this before)
'delivered a calmness did you say?' is the wordplay.
'delivered' becomes 'centre' (I can't explain this - if you can you should give a lot more credence to this answer).
'a calmness' becomes 'peace' (peace is a kind of calmness).
'did you say?' indicates a 'sounds like' (homophone) clue.
'peace' sounds like 'piece'.
'centre'+'piece'='CENTREPIECE'
(Other definitions for centrepiece that I've seen before include "Principal item in display" , "Most important object in picture etc" , "Most significant feature" , "table decoration" , "focus of attention" .)