Find expression? Only part of it in list (5)
I believe the answer is:
index
'list' is the definition.
(I know that index is a type of list)
'find expression? only part of it' is the wordplay.
'only part of it' says the answer is hidden in the clue.
'INDEX' is hidden within 'find expression'.
'in' acts as a link.
(Other definitions for index that I've seen before include "List of topics etc" , "List at end of book" , "Alphabetical register" , "List of contents in book" , "It points" .)