Element; canister (3)
I believe the answer is:
tin
This clue is a double definition.
'element' is the first definition.
(tin is a kind of element)
'canister' is the second definition.
(I know that canister can be written as tin)
(Other definitions for tin that I've seen before include "Silvery white metal" , "A silvery-white metal, symbol Sn" , "Atomic number 50" , "Money" , "Silvery metallic element" .)