Tear canal (4)
I believe the answer is:
duct
'tear canal' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for duct that I've seen before include "Pipe conveying fluid or gas" , "The Eve of St - is a narrative poem by Keats" , "Tube, passageway" , "Enclosed conduit for fluid" , "Tube for cables, air, etc" .)