Here be spoilers!
I was under the impression, given the name, that the team of Avengers are avenging the death of one of the team (sometimes it's the extended team). So in A:IW, who is being avenged?
The reason I ask is ... so many die.
The IMDB trivia page for The Avengers says, "Agent Phil Coulson... is killed off in the middle of the film, giving the Avengers someone to avenge."
The IMDB trivia page for Avengers: Age of Ultron says, "For the first time, a major hero ... dies permanently in the Marvel Cinematic Universe."