The Canadian singer, whose real name is Claire Elise Boucher, gave birth to her first child with Musk on 4 May 2020.
However, speculation arose that the unusual moniker might not comply with the law in California, where the couple live.
According to Californian law, names must be written on birth certificates “using the 26 alphabetical letters of the English language”, however apostrophes and dashes can be included.
Just under a month after the couple announced the name change, the baby’s name was officially confirmed on his birth certificate, according to TMZ.
On the birth certificate, it states that the baby’s first name is “X”, it’s middle name is “AE A-XII” and its last name is “Musk”.
The couple went on to reveal the meaning behind their son’s unusual name.
Writing on Twitter, Grimes explained that the first “X” is a reference to the unknown variable commonly used in mathematical sums.
“Æ”, which comes next, is the Elven spelling of AI, which is shorthand for artificial intelligence and translates to “love” in several languages such as Mandarin and Japanese.
Next in the name is “A-12”, which Grimes explains is a precursor to the aircraft SR-71, which she and Musk love because it is “great in battle but non-violent”.
The A in ”A-12” is also short for Archangel, which Grimes says is her favourite song.
“I mean it’s just X, the letter X,” the Tesla CEO said, adding: “Um, and then, the Æ is, like, pronounced ‘Ash’. And then, A-12, A-12 is my contribution.”
During the interview, the SpaceX founder also acknowledged that Grimes was the one who had chosen the name, saying: “First of all, my partner is the one that, actually, mostly, came up with the name.”
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