Toothpaste holder (4)
I believe the answer is:
tube
'toothpaste holder' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tube that I've seen before include "appearing tinny?" , "Pack of toothpaste; type of train" , "Hollow body for the underground" , "Pipe or hose" , "train network" .)