When the usually playful Elon Musk on Monday announced the name of his newborn son, "X Æ A-12," on Twitter, many thought he was joking. And since then the name choice has flourished in various memes on social media where many ask themselves how it is actually pronounced.

Grimes explained on Twitter the mythological meaning of the name. X represents an unknown variable, Æ is the "Alvisk" spelling of Grime's name and A-12 is an aircraft model used by the US intelligence service CIA during the Cold War.

Can be denied

Under California law, however, a given name may only contain the 26 letters of the English-language alphabet. Thus, the name may be denied.

Grimes and Elon Musk have been a couple since May 2018 and revealed in January that they were expecting their first joint child.