The MCU has released four Avengers movies thus far, but the team’s name only starts to make sense after Infinity War and during the events of Endgame.
In Captain Marvel, we learned that Nick Fury came up with the name for the Avengers Initiative through Carol Danvers’ call sign when she was in the Navy. As far as explanations go, that was a neat twist, but Earth’s Mightiest Heroes didn’t really do a whole lot of avenging before the events of Endgame.
When you think about it, the first movie revolved around Loki’s invasion of Earth through the Chitauri and when the God of Mischief wounds Agent Coulson, Fury uses this as a means to motivate the disgruntled band of heroes. But the main reason for them teaming up hardly had anything to do with avenging the S.H.I.E.L.D. agent. In the sequel, meanwhile, Avengers: Age of Ultron, the dissonance is even stronger. Ultron was a creation of Tony Stark, and he didn’t really cause that much destruction as to compel the heroes to exact retribution.
Even in the threequel, the Avengers are mostly on the defensive, trying to stop the Mad Titan from getting his hands on all the Infinity Stones. In fact, it’s only after Thanos succeeds in wiping half of all living creatures from existence that the purpose behind the name of the Avengers comes to fruition.
After failing to save the world, twice, Avengers: Endgame shows us the aftermath of that failure by depicting the MCU heroes in a state of defeat and depression. It’s here that the team finally earns their name, though, and puts everything on the line to make things right and take revenge on Thanos, with some of them even playing the ultimate hero card of sacrifice to ensure victory over the Mad Titan.