A salt shaker you could buy in a bookshop (5)
I believe the answer is:
atlas
'buy in a bookshop' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'a salt shaker you' is the wordplay.
'a salt' anagrams to 'ATLAS'.
But, I'm not sure how the anagram is indicated.
'could' acts as a link.
Can you help me to learn more?
(Other definitions for atlas that I've seen before include "North African mountains - mythical Titan" , "Book of geography" , "Collection of maps" , "I carry a huge weight" , "Ballistic missile" .)