As well as Dan could be (3)
I believe the answer is:
and
'as well as' is the definition.
(I've seen this in another clue)
'dan could be' is the wordplay.
'could be' is an anagram indicator.
'dan' is an anagram of 'AND'.
(Other definitions for and that I've seen before include "Joiner or dandies" , "It connects words, clauses or sentences" , "It's used to connect words, clauses or sentences" , "Joining word" , "Word to connect" .)