Wonder Woman's "costume" isn't a costume or a uniform: it's a "religious garment," according to the Amazonian warrior herself.
Diana made the clarification in this week's Justice League #35, from writer Christopher Priest and artist Pete Woods (h/t Bleeding Cool).
The events of Justice League #34 resulted in a nun killed by a terrorist wielding Wonder Woman's sword, and the subsequent issue sees Diana's prized weapon confiscated by the police — who then subject the heroine to an interrogation.
"Your costume," begins New York City Police Department Officer Ryan, who is swiftly cut off by Diana. "It's a habit," she says, succinctly.
"Well, yes," he says, "I'd assume dressing like that becomes a habit."
"A habit, Mr. Ryan," Diana says, "A religious garment. I do not wear 'a costume.'"
The issue is pressed further when Diana clarifies her name isn't "Diana Prince."
"Diana of Themyscira. Daughter of Hippolyta," Diana points out.
"And that's all you're going to give me," Ryan says.
"That's all there is, Mr. Ryan."
It remains to be seen if Wonder Woman's live-action counterpart, played by Gal Gadot, will ever reject her man-made surname of "Prince."
The heroine has fully embraced her "Diana Prince" name in modern day, and the DCEU version of the character is likely to keep it as "Prince" was, in a way, "given" to her by brief lover Steve Trevor (Chris Pine) — who said her last name was "Prince" after the Amazon, new to the world of man, nearly introduced herself as "Diana, Princess of Themyscira."
The Wonder Woman movie similarly treated the superheroine's armored garb as more than just a "costume."
Gal Gadot recently reprised the role in Justice League and will next appear in Wonder Woman 2, opening November 1, 2019.