Signatories embrace alliance (4)
I believe the answer is:
nato
'alliance' is the definition.
(I know that NATO is a type of global organization)
'signatories embrace' is the wordplay.
'embrace' says the answer is hidden in the clue (I've seen 'embracing' mean this (the solution is embraced by words in the clue)).
'NATO' is hidden within 'signatories'.
(Other definitions for nato that I've seen before include "Military/political alliance" , "Western mil. alliance" , "International organisation for collective security" , "Military alliance, formed 1949" , "Collective security alliance engaged in Bosnia" .)