Container with a line in waterway (5)
I believe the answer is:
canal
'waterway' is the definition.
(I've seen this before)
'container with a line' is the wordplay.
'container' becomes 'can' (can is a kind of container).
'with' means one lot of letters go next to another.
'line' becomes 'l'.
'can'+'a'+'l'='CANAL'
'in' is the link.
(Other definitions for canal that I've seen before include "navigate this?" , "Man-made watercourse" , "Man-made strip of water" , "Duct" , "Artificial waterway for barges" .)