Megan Pineda of Billinghurst Middle School emerged victorious over 30 other competitors Saturday in Las Vegas in the event sponsored by the Las Vegas Review-Journal.
She advances to the national championship in Washington from May 27 to June 1.
The 12-year-old Pineda told the Review-Journal that she had never heard of the word jovicentric, let alone considered spelling it.
The word means to revolve around the planet Jupiter.
Jake Gottschalk, an eighth grader at Cashman Middle School in Las Vegas, was the runner-up.