Military alliance with headquarters in Belgium (4)

I believe the answer is:

nato

(Other definitions for nato that I've seen before include "Military organization" , "Military/political alliance" , "US/Europe alliance" , "Military alliance, formed 1949" , "Military bloc" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.