Mite - different thing (4)
I believe the answer is:
item
'thing' is the definition.
(thesaurus)
'mite different' is the wordplay.
'different' is an anagram indicator.
'mite' with letters rearranged gives 'ITEM'.
(Other definitions for item that I've seen before include "Article (on list or in news)" , "Record" , "Part of a list" , "One thing on a list" , "Piece in paper" .)