Comic Book Questions Answered – where I answer whatever questions you folks might have about comic books (feel free to they're e-mail questions to me at email@example.com).
Reader Bret S. wanted to know where the name "Iron Man" came from in the films, since his armor wasn't made out of iron like it was in the comics.
As Bret correctly notes, the name "Iron Man" made perfect sense in the comics, as in Tales of Suspense #39 (by Stan Lee, Larry Lieber and Don Heck), the injured Tony Stark builds his original armor out of iron...
And when he gets back home in the next issue, he still uses that original iron armor in battle as the superhero known as, of course, Iron Man...
So even when he changes the material that his armor is made out of later on, the name had already stuck.
In the movie, however, things go differently.
He still builds a basic version of the armor, but instead of an "iron lung," his heart is powered by his arc reactor technology...
And he doesn't use that original armor as a superhero back in the United States. In fact, he doesn't actually take on a superhero name at ALL.
So why "Iron Man"?
The answer is that the media came up with the name in the movie universe.
The media likely is either referring to the actual term "iron man," meaning "an incredibly strong or robust man" or the Black Sabbath song, which obviously existed in this universe BEFORE Iron Man's debut, unlike in the comic book universe, where the song came out years after the character.
In either event, Tony even notes in the film that the name doesn't make sense, since his armor is not made out of iron, but since it had gained popularity, he decided to go with it at his press conference, where he revealed that he was, in fact, the Iron Man (although he shortened it to just simply "I am Iron Man."
Thanks for the question, Bret!
If anyone else has a question about comics (or, I guess, comic book movies), drop me a line at firstname.lastname@example.org!