More than one tin article in case of canvas (4)
I believe the answer is:
cans
'more than one tin' is the definition.
('can' can be a synonym of 'tin')
'article in case of canvas' is the wordplay.
'article' becomes 'an' (English indefinite article).
'in' is an insertion indicator.
'case of' says to hollow out the word (remove centre letters) (like emptying a case).
'canvas' with its centre taken out is 'cs'.
'an' placed into 'cs' is 'CANS'.
(Other definitions for cans that I've seen before include "Metal containers" , "Headphones" , "Tins" .)