Come out east and join (6)
'come out' is the definition.
('emerge' can be a synonym of 'come out')
'east and join' is the wordplay.
'east' becomes 'e' ('E' can be a synonym of 'east').
'and' says to put letters next to each other.
'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".)