How 'algorithm' got its name from a 9th-century Persian mathematician

The first microcomputer named "Micral N" was created by the French engineer Francois Gernelle in 1973, five years before Apple and 3 years before IBM. Guillaume Souvant/AFP hide caption

It's a simple word that has developed a sinister connotation: algorithm. For many of us, algorithms help determine what we watch, read and listen to — in the process, confirming our tastes and biases , and creating ideological echo chambers .

The word might not seem like one that would get much consideration from the Holy See. But last month in his first encyclical , Pope Leo XIV addressed the potential dangers of artificial intelligence. The word "algorithm" came up 19 times.

Pope Leo XIV waves as he leaves after his weekly general audience in St. Peter's Square at The Vatican, Wednesday, May 27, 2026. Alessandra Tarantino/AP hide caption

As part of NPR's " Word of the Week " series, we're looking at the history of the word that's defined much of modern life — and in the process, we'll blow the dust off some ancient mathematical concepts.

The etymology of the word is a strange one, according to Rob Watts, a journalist and host of RobWords , a popular YouTube channel about word origins and usage. "It just sounds like a mathematical term," he notes. Instead, it invokes a specific mathematician, he says: the 9th century Persian Muhammad ibn Musa al-Khwarizmi.

"It's actually the Latin take on that name al-Khwarizmi that we're invoking when we use the word algorithm," Watts says.

But it's taken a rather convoluted journey to reach us a dozen centuries later. The modern word algorithm traces back to the Latin algorismus through French ( algorisme) and English ( algorism). It also got "somewhat conflated with the term " arithmetic " before arriving in its current form, Watts says.