Come out east and join (6)
I believe the answer is:
'come out' is the definition.
'east and join' is the wordplay.
'east' becomes 'e' (abbreviation).
'and' means one lot of letters go next to another.
'join' becomes 'merge' (I've seen this before).
(Other definitions for emerge that I've seen before include "Come out or become known" , "Come out or transpire" , "Come into greater prominence" , "Rise to notice" , "Become known or apparent" .)