Cylindrical conduit (4)
I believe the answer is:
pipe
'cylindrical conduit' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pipe that I've seen before include "It can be played or smoked" , "Wine cask; sing shrilly" , "11th" , "Utter shrilly; wine cask" , "Main provider" .)