For international pop star Katy Perry and Australian fashion designer Katie Perry, the answer can be found in a slight variation in spelling and more than six years of litigation.
The fight over the rights to the Katie/Katy Perry name began when the designer - now known as Katie Taylor - sued the performer behind Firework and Roar for trademark infringement.
The US singer, whose real name is Katheryn Hudson, hit back with a bid to cancel the designer's trademark, arguing it was likely to harm her reputation or deceive shoppers.
The dispute dragged on for over six years after the pop star successfully overturned an initial Federal Court ruling that the designer's trademark had been infringed.
But it came to a decisive end on Wednesday when the nation's highest court decided the David-and-Goliath battle in favour of the Australian.
The designer's mark was not in breach of trademark law and was not likely to harm the Dark Horse singer's reputation or cause confusion, the High Court ruled in a majority decision.
After years fighting to hold onto the label she has spent nearly 20 years building, Ms Taylor hailed the ruling as a victory for small businesses everywhere.
"I am absolutely over the moon," Ms Taylor said in a statement to AAP.
"It honestly feels like a dream."
Her lawyers argued during the High Court hearing that shoppers were savvy enough to distinguish between the two spellings and wouldn't connect the label to the pop star.
The designer said she didn't know of the singer's existence when she first sought the clothing trademark in 2007.
But by the time Ms Taylor applied to trademark the name Katie Perry, she had heard I Kissed a Girl on the radio and bought the song on iTunes.
There was no way she could have known how famous Ms Hudson would become, her lawyer told the High Court in September.
But the pop star's lawyers contended Ms Taylor should have made a complaint earlier instead of waiting 10 years after the sale of Katy Perry-branded merchandise began.
The designer faced the possibility of having the Katie Perry trademark de-registered after her 2023 win in the Federal Court was overturned on appeal.
The appeal judges found the designer's mark was deceptively similar to the pop star's brand and was likely to cause confusion.
But they had made a mistake in concluding there were grounds for its cancellation, the High Court determined in its majority ruling.
The decision marks the end of a tug-of-war that has been running since 2009, when Ms Hudson became aware the designer had applied to register the Katie Perry trademark.
According to court documents, the superstar told her talent agent Steven Jensen to "keep me outta it entirely".
"I wouldn't have even bothered with this (if) mtv hadn't picked up this silliness," she wrote in an email.
"Dumb bitch! Rawr!"
The singer is on the hook to foot Ms Taylor's legal bill, with the figure to be determined at a later date.
The designer is celebrating with her family before returning to designing clothing.
"It's been a long road, but I'm excited to move forward," she told AAP.
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