Horse-drawn vehicle (7)
(Other definitions for phaeton that I've seen before include "Coach" , "transport" , "4-wheeled carriage" .)
'horse-drawn vehicle' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for chariot that I've seen before include "Two-wheeled horse-drawn vehicle in ancient Rome" , "Two-wheeled horse-drawn vehicle used in battle" , "ceremonial carriage" , "Ben Hur transport?" , "ride in carriage" .)