Come together as one (8)
I believe the answer is:
coalesce
'come together as one' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for coalesce that I've seen before include "Grow together, amalgamate" , "'Fuse, combine (8)'" , "Fuse or cause to grow together" , "Combine with others as political parties may do" , "Join into one mass" .)