Vehicle turned into the ancient region (6)
I believe the answer is:
thrace
'ancient region' is the definition.
'thrace' can be an answer for 'region' (Thrace is an example). I am not sure about the 'ancient' bit.
'vehicle turned into the' is the wordplay.
'vehicle' becomes 'car' (car is a kind of vehicle).
'turned' shows that the letters should be reversed in order.
'into' means one lot of letters goes inside another.
'car' in reverse letter order is 'rac'.
'rac' going inside 'the' is 'THRACE'.
Can you help me to learn more?
(Other definitions for thrace that I've seen before include "ancient land" , "old part of Europe" , "The car (anag.); historical region" , "Region of SE Balkans" , "Balkan area" .)