Less than a tiny container (3)
I believe the answer is:
tin
'container' is the definition.
(I know that tin is a type of container)
'less than a tiny' is the wordplay.
'less than' means to remove the last letter (not the full word).
'tiny' with its final letter taken off is 'TIN'.
(Other definitions for tin that I've seen before include "Silver-white element often used in food containers" , "Light metal" , "Money" , "A silvery-white metal often in cans" , "Silver-white metal, used to make cans" .)