It paves the way (3)
I believe the answer is:
tar
'it paves the way' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tar that I've seen before include "Viscous liquid; sailor" , "It may cover the road" , "It paves the way" , "Sticky substance - seaman" , "Viscous mixture - sailor" .)