Locomotive (6)
'locomotive' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for engine that I've seen before include "Motive machine" , "Machine with moving parts" , "turn of mind once" , "Power unit" , "search, maybe" .)
'locomotive' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for train that I've seen before include "Suite; give practice (in)" , "Try to get fit" , "one thing after another" , "held up in union action?" , "Teach, retinue" .)
'locomotive' is the definition.
(iron horse is a kind of locomotive)
This is all the clue.
(Other definitions for iron horse that I've seen before include "worn-out engine" , "An invention of the steam age" , "Old name for locomotive" , "one's gone off the rails" , "Train leader" .)