The late Bill Russell is getting the ultimate tribute -- the NBA just announced the Celtics legend's No. 6 will be retired throughout the league ... making him the first player to receive such an honor.
The Association just announced the move minutes ago ... with commish Adam Silver explaining the decision.
"Bill Russell's unparalleled success on the court and pioneering civil rights activism deserve to be honored in a unique and historic way," Silver said. "Permanently retiring his No. 6 across every NBA team ensures that Bill's transcendent career will always be recognized."