The way to break a rod (4)
I believe the answer is:
road
'the way' is the definition.
(road is a kind of way)
'break a rod' is the wordplay.
'break' indicates anagramming the letters.
'a'+'rod'='arod'
'arod' with letters rearranged gives 'ROAD'.
'to' acts as a link.
(Other definitions for road that I've seen before include "Route travelled by sea" , "mine gallery" , "For place to anchor" , "'The . . . . to hell is paved with good intentions'" , "Highway or byway" .)