Part includes old time turn (8)
I believe the answer is:
rotation
'turn' is the definition.
(I know that rotation is a type of turn)
'part includes old time' is the wordplay.
'part' becomes 'ration' (ration is a kind of part).
'includes' indicates putting letters inside.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'time' becomes 't' (abbreviation).
'o'+'t'='ot'
'ration' placed around 'ot' is 'ROTATION'.
(Other definitions for rotation that I've seen before include "Turn of a wheel" , "The action of moving around an orbit" , "Spinning motion or cyclic changes as of crops" , "Cycle - revolution" , "Action of turning" .)