Powerful symbol used regularly in mezangelle (5)
I believe the answer is:
eagle
'powerful symbol' is the definition.
(symbol of the USA)
'regularly in mezangelle' is the wordplay.
'regularly in' indicates alternate letters.
The alternating letters of 'mezangelle' are 'EAGLE'.
'used' acts as a link.
(Other definitions for eagle that I've seen before include "Large bird of prey" , "Symbolic American bird" , "Old comic" , "Bird of prey; former children's comic" , "Bird with hooked bill and long broad wings" .)