With the release of Avengers: Endgame came the shocking reveal that Thor had let himself go during the 5 year time skip, looking very much like The Dude from The Big Lebowski, so much so that Tony Stark even calls Thor “Lewboski” at one point. The character had become overweight and had let his hair become unruly whilst he spent his days drinking in Norway.
For the most part, fans have referred to this new Thor as either Fat Thor or Lewboski Thor, but it turns out that Marvel have their own name for this new iteration of the God of Thunder, Bro Thor.
One of the bonus extras included in the home release for Avengers: Endgame is titled “Bro Thor” and is accompanied with the following description; “His appearance has changed but his heroism remains! Go behind the scenes to see how Bro Thor was created.”
Bro Thor seems a very apt nickname for this current version of the character. It puts less of a focus on his physical appearance and more of a focus on the way the character actually acts, as seen when Hulk and Rocket visit Thor in Norway to discover that he has been spending his days getting drunk and playing Fortnite with Korg and Meek.