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 into existence", "Come out or surface", "Come out or transpire", "Rise to notice", "Come into view".)