Last year, 146 American girls were named Khaleesi. That's a 450% jump in the name's usage from 2011, and before that year it was completely unknown.

If you're not familiar with the name Khaleesi, you'd be excused for guessing that it's Arabic, like Khalilah, or perhaps from Western Africa, like Kwasi. In fact, the name comes from the Dothraki language. Except it's not a name in that language, but a common word meaning "queen." And Dothraki isn't a natural language, but a handful of words created by Game of Thrones author George R. R. Martin for his imagined Dothraki people. (A language-creation specialist has since elaborated on Martin's vocabulary for the TV version of his fantasy epic.)

Plenty of authors dating back to Shakespeare have invented names that caught on with parents. You can even find names from imagined fantasy worlds that have been used on real-world babies. For instance, hundreds of American girls have been named Eowyn over the past decade after a Lord of the Rings character. (Read more about fantasy and science fiction names.) But a name taken from a word that's not a name, from an imagined language? I can't think of a precedent.

That's not to say we couldn't see this one coming. More than a year ago, I raised this question on Twitter:

"Game Of Thrones fans, help! A user added the title Khaleesi to our baby name db. Legit? Could you see it as a name?"

Among the responses, one Twitter denizen with the handle "pantalonesfuego" offered a key insight:

"To me the name Khaleesi feels a little different from Queen because it's also a form of address -- like 'Your Highness'"

This distinction means that Khaleesi, while not a name, was used on the TV series in a name-like way.

Another Twitterer, PanyaV, further pointed out that the TV series altered the pronunciation of Khaleesi in a way that might appeal to American parents. The Kh- was supposed to indicate a "voiceless velar fricative," the throaty sound that's common in many languages but hard to pronounce in English. What's more, the Dothraki word was supposed to be stressed on the first syllable. Instead, though, viewers hear the name-ready pronunciation "kah-LEE-see." Some parents even chose to simplify the name's spelling to make this pronunciation clear; the variant Kaleesi was given to 30 babies.

As all of these young Khaleesis and Kaleesis grow up, they will doubtless be asked about their names. They could launch into an awkward origin story ("Umm, well, my parents really liked this TV show..."), but I recommend a simpler approach:

"It's Dothraki for 'queen.'"