Advertisement for mice or clam chowder (10)
I believe the answer is:
commercial
'advertisement' is the definition.
(I know that commercial is a type of advertisement)
'mice or clam chowder' is the wordplay.
'mice or clam' can be anagrammed to 'COMMERCIAL'.
However, I'm not clear how the anagram is indicated.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for commercial that I've seen before include "Greek island" , "in demand?" , "plug" , "TV ad" , "Television advert" .)