A key area for a Turkish commander (3)
I believe the answer is:
aga
'turkish commander' is the definition.
(I've seen this before)
'a key area for a' is the wordplay.
'a key' becomes 'g' (I've seen this in other clues**).
'area' becomes 'a' (maths abbreviation).
'for' says to put letters next to each other (I've seen this in other clues).
'g'+'a'='ga'
'ga' after 'a' is 'AGA'.
(Other definitions for aga that I've seen before include "Kitchen range" , "Type of stove" , "Cooker" , "Oven" , "Kitchen stove" .)