Blend, coalesce (5)
I believe the answer is:
merge
I believe this clue is a double definition.
'blend' is the first definition.
(synonyms)
'coalesce' is the second definition.
(synonyms)
(Other definitions for merge that I've seen before include "Combine to form a single entity" , "Fuse" , "Amalgamate" , "Make one" , "Become one" .)