According to a New York Times interview with the artist, published Wednesday, Grimes, whose real name is Claire Boucher, now goes by "c" — which she says is a reference to the speed of light.
A single-letter nickname is something Grimes now has in common with her 5-month-old, who goes by "X" for short. C, 32, shares X with her boyfriend, SpaceX CEO Elon Musk, 49.
Though X is still an infant, his mother claims he's already developed sophisticated taste in media.
"I’ve watched 'Apocalypse Now' and stuff with my baby," she said. "He's into radical art. Like, he just actually is, and I don't think it's problematic to engage with them on that level."
Grimes (as she was known then) and Musk made headlines after announcing the birth of their son, and his unusual name, on Twitter in May. A day later, Grimes tweeted a full breakdown of the name choice:
"•X, the unknown variable
•Æ, my elven spelling of Ai (love &/or Artificial intelligence)
•A-12 = precursor to SR-17 (our favorite aircraft). No weapons, no defenses, just speed. Great in battle, but non-violent
+ (A=Archangel, my favorite song) (metal rat)"
However, Grimes apparently made a mistake in her explanatory post, which Musk corrected.
"SR-71, but yes," he wrote in response.
Musk later broke down how to pronounce the name on the Joe Rogan Experience podcast. The X is pronounced "like the letter, X," Æ is pronounced “ash,” and A-12 ("my contribution") is said how it appears. Thus "X-Ash-A-12."
Later that month, Grimes revealed in a series of Instagram comments that the couple had slightly changed their son's name to "X Æ A-XII." California law limits names to the 26 letters of the English alphabet and certain punctuation like hyphens, apostrophes, periods and commas.
"Roman numerals," she explained. "Looks better tbh … one dash is allowed."
Musk gave credit to the child's mother, who "mostly came up with the name. She's great at names," and said "babies are awesome. They're little love bugs."
According to the NYT article, C is working with the tech company Endel to create an "AI Lullaby," a soothing soundtrack of ambient noise to help infants fall asleep.
C said her quest for "a better baby sleeping situation" for X inspired her to develop the lullaby.
"When you have a baby, you’re always using white-noise machines," she said. "It’s much easier to get them to sleep if you train them on some kind of audio situation. And so I was just, like, could this be more artistic?"
According to C, babies "do have taste."
"They definitely like some things," she continued. "They don’t like other things. They fully have opinions."
C also described how she used X's feedback to make the lullaby.
"The first version, there was too many sort of sharp bells, and it caused tears and just general chaos," she said. However, as she made adjustments, she'd find that "X would smile more and stuff."
Contributing: Hannah Yasharoff, Bryan Alexander
This article originally appeared on USA TODAY: Grimes now goes by 1 letter, gives update on 5-month-old son X Æ A-XII