On Monday, Elon Musk welcomed his first child with singer Grimes.
The billionaire CEO of Tesla and SpaceX announced the birth to 33 million of his followers with a tweet saying "Mom & baby all good" and then went on to add a rather unexpected surprise - the baby boy would go by the name of "X Æ A-12 Musk."
Here's what it means.
Mysterious name triggered a wave on social media
When Musk announced the gender-neutral name, X Æ A-12 started trending on Twitter, with many questioning how the name would be pronounced and what does it really mean.
Some people even thought that Musk, who has a knack for cracking jokes on Twitter (occasionally costing him millions), might not be actually serious about keeping this name.
However, Grimes offered up clarification
As people tried to solve the puzzle, Grimes took to Twitter to confirm the name and offer its meaning.
The Canadian singer said while "X" is an unknown variable, "Æ" is her "elven spelling of Ai (love &/or Artificial intelligence)" and "A-12" is the precursor to SR-17, their favorite aircraft.
"No weapons, no defenses, just speed. Great in battle, but non-violent," she added.
A-12 was internally known as 'Archangel'
Notably, A-12, which was developed for the Central Intelligence Agency by Lockheed Martin, went by the internal name of 'Archangel,' which Grimes added was also her favorite song.
Here is Grimes's clarification
•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)