Reduced very small container (3)
I believe the answer is:
tin
'container' is the definition.
(tin is a kind of container)
'reduced very small' is the wordplay.
'reduced' means to remove the last letter.
'very small' becomes 'tiny' (I've seen this before).
'tiny' with its final letter removed is 'TIN'.
(Other definitions for tin that I've seen before include "Light metal" , "A silvery-white metal, symbol Sn" , "A silvery-white metal often in cans" , "Earnings" , "Money" .)