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The 48-year-old tech entrepreneur and the Canadian singer welcomed their first child together on May 5, revealing to the world that they opted for a rather elaborate name for the boy, X Æ A-12.
On Tuesday, Grimes, 32, took to Twitter to break down and explain what each part of her son’s name actually means. In her tweet, she notes that the “A-12” part of the child’s name is a reference to the “precursor to SR-17 (our favorite aircraft).”
“No weapons, no defenses, just speed. Great in battle, but non-violent,” she added.
Later, Musk chimed in to note what many aviation experts likely already noticed. She had accidentally swapped the numbers of the SR-71 blackbird, calling it the “SR-17.”
"SR-71, but yes," Musk corrected.
“I am recovering from surgery and barely alive so may my typos b forgiven but, damnit,” Grimes responded. “That was meant to be profound.”
That’s when Musk softened the correction by responding by calling her “powerful."
The rest of Grimes' tweet appears to be accurate, with her breaking down each piece of her newborn’s moniker.
“X, the unknown variable," the singer wrote first, adding an emoji of two crossing swords. "Æ, my elven spelling of Ai (love &/or Artificial intelligence)."
She concluded by writing the “(A=Archangel, my favorite song) (metal rat)."
The baby is Grimes' first child. Musk has five sons from a previous marriage. Musk's first son reportedly died of sudden infant death syndrome at 10 weeks old, back in 2002.
Grimes, whose real name is Claire Boucher, discussed her pregnancy in March with Rolling Stone. The musician told the magazine she was expecting her child to be nocturnal, as the baby moved "only" at night during her pregnancy.
Grimes and Musk have been dating since 2018.
Fox News' Nate Day contributed to this report.