Space to reverse round front of traction engine (5)
I believe the answer is:
motor
'engine' is the definition.
(thesaurus)
'space to reverse round front of traction' is the wordplay.
'space' becomes 'room' (room is a kind of space**).
'to reverse' is a reversal indicator.
'round' indicates putting letters inside.
'front of' indicates taking the first letters.
The first letter of 'traction' is 't'.
'room' in reverse letter order is 'moor'.
'moor' placed around 't' is 'MOTOR'.
(Other definitions for motor that I've seen before include "Travel by car, engine" , "Driver" , "Engine - relating to movement" , "Engine of vehicle" , "(Transport using) engine" .)