You’ve probably seen the memes. Every time Elon Musk announces a new addition to his growing family, the internet basically has a collective meltdown over the names. Are they serial numbers? Secret codes for Martian colonies? Honestly, it’s a lot to keep track of, especially now that the count has reached 14 children as of early 2026.
It’s easy to get lost in the "X Æ A-Xii" of it all, but there is actually a method to the madness. From the more traditional names of his first six children with Justine Wilson to the sci-fi-inspired monikers of his kids with Grimes and Shivon Zilis, each name tells a specific story about Musk's obsessions—AI, space travel, and deep-time physics.
The Early Years with Justine Wilson
Before the eccentric names became a global talking point, Musk’s first marriage to Canadian author Justine Wilson resulted in six children. It wasn't exactly a smooth start. Their first son, Nevada Alexander, was born in 2002 but tragically passed away from Sudden Infant Death Syndrome (SIDS) at just 10 weeks old. It's a heavy part of the family history that Musk rarely discusses publicly, though it clearly shaped his perspective on family.
Following the loss of Nevada, the couple turned to IVF. In 2004, they welcomed twins: Griffin and Vivian. Interestingly, Vivian was born Xavier, but she legally changed her name and gender in 2022. She also dropped the "Musk" surname entirely, choosing to go by Vivian Jenna Wilson. She’s been pretty vocal about her estrangement from her father, once calling him a "pathetic man-child" in an interview.
Two years later, in 2006, the family expanded again with triplets: Kai, Saxon, and Damian. These names are relatively "normal" by today's standards, though still fairly distinct.
Decoding the Grimes Era: X, Y, and Tau
When Elon Musk and the musician Grimes (Claire Boucher) started dating, everyone knew the names were going to get weird. They didn't disappoint. Their first son, born in 2020, was famously named X Æ A-12.
Wait, how do you even say that? According to Musk on the Joe Rogan podcast, it’s "X Ash A Twelve."
- X is the unknown variable.
- Æ is the "elven" spelling of AI (Love and/or Artificial Intelligence).
- A-12 is a nod to the Archangel-12, the precursor to the SR-71 Blackbird, which happens to be Musk’s favorite aircraft because it has no weapons, just pure speed.
Because California law is a bit picky about using numbers in names, they eventually changed it to X Æ A-Xii. They just call him "X" for short.
Then came their daughter, Exa Dark Sideræl Musk, born via surrogate in December 2021. Her nickname is "Y."
- Exa refers to the supercomputing term exaFLOPS.
- Dark represents the unknown, or dark matter—the "beautiful mystery" of the universe.
- Sideræl (pronounced sigh-deer-ee-el) is a "more elven" spelling of sidereal, which refers to star time rather than Earth time.
The world didn't even know about their third child, Techno Mechanicus, until Walter Isaacson’s biography dropped in 2023. This little guy goes by "Tau." For those who aren't math nerds, Tau represents the mathematical constant equal to $2\pi$, which is roughly 6.28.
The Neuralink Connection: Shivon Zilis
While things were getting complicated with Grimes, Musk was also expanding his family with Shivon Zilis, an executive at his company Neuralink. This part of the timeline gets a little messy because some of these kids were born within weeks of the children with Grimes.
In November 2021, Zilis gave birth to twins: Strider Sekhar Sirius and Azure Astra Alice.
- Strider is almost certainly a reference to Aragorn from Lord of the Rings.
- Azure and Astra lean into the blue-sky and space themes Musk loves.
The family grew even larger in February 2024 when Arcadia Musk was born. The name Arcadia evokes a Greek vision of pastoralism and harmony with nature—a bit of a departure from the tech-heavy names, though still very "epic" in feel.
But wait, there's more. In early 2025, Zilis announced the birth of another son, Seldon Lycurgus.
- Seldon is a clear tribute to Hari Seldon, the protagonist of Isaac Asimov’s Foundation series. If you know anything about Musk, you know he's obsessed with the idea of "psychohistory" and saving civilization.
- Lycurgus refers to the legendary lawgiver of Sparta. Basically, the kid is named after a galactic mathematician and a Spartan ruler. No pressure, right?
The Newest Additions and the 2026 Landscape
As of January 2026, the count reportedly stands at 14. The most recent addition to the public record is Romulus Musk, born in September 2024 to influencer Ashley St. Clair.
Romulus, of course, is the legendary founder of Rome. It fits the pattern of "foundational" or "ruler" names that Musk seems to gravitate toward lately. While Musk hasn't been as public about Romulus as he has been with X, paternity was confirmed through legal filings in 2025.
Why the Strange Names?
You might wonder if this is just a billionaire being eccentric. Sorta. But if you look at the names collectively, they reflect a specific worldview. Musk is obsessed with the "long-term" future of humanity. He chooses names that aren't tied to specific cultures or traditions, but rather to math, science, and the stars.
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It’s a "blank slate" approach to identity.
Understanding the Legal and Social Reality
Living with these names isn't always easy. Vivian Wilson’s decision to drop the Musk name entirely shows the personal friction that can exist behind the headlines. While "X" is being groomed as a mini-tech mogul—often appearing at SpaceX launches and even in the Oval Office—other children are kept far away from the spotlight.
Grimes has been vocal about wanting to keep "Y" and "Tau" out of the public eye, leading to some high-profile custody disagreements. It's a reminder that while the names are fun for the internet to talk about, these are real kids growing up in a very unusual family dynamic.
Actionable Takeaways for Following the Story
If you're trying to keep up with the ever-changing Musk family tree, here is how to navigate the noise:
- Check the Mothers: The names usually follow the "vibe" of the mother. Justine’s kids have classic, strong names. Grimes’ kids have "elven" and tech-coded names. Shivon’s kids have names rooted in sci-fi and mythology.
- Watch the Nicknames: Most of the kids don't actually go by their full legal names. X, Y, and Tau are the standard.
- Look for the Source: Most official name reveals now happen via X (formerly Twitter) or through authorized biographies rather than traditional press releases.
The Musk family tree is essentially a living map of one man’s attempt to "techno-morph" the world, starting with his own legacy. Whether these names will eventually seem normal in a future Mars colony or remain as oddities of the 2020s is something only "star time" will tell.