East European boom? (4)
I believe the answer is:
pole
I believe this is a double definition.
'east european' is the first definition.
'boom?' is the second definition.
(boom is a kind of pole)
(Other definitions for pole that I've seen before include "location where it is always very cold" , "flag-bearer" , "Native of Warsaw" , "One of two opposites" , "National from east" .)