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Leonardo of Pisa is best known as Fibonacci; various stories found in books and on the web claim that the name Fibonacci was invented by Edouard Lucas or Guillaume Libri in the 19th century, and that it means "son of Bonacci" (Leonardo's father was apparently called Guglielmo Bonaccio). Heinz Lueneburg found out that the name Fibonacci had been used already by John Leslie in 1820.

Are there any facts known as to who, why and when invented the name Fibonacci? Or wasn't it invented at all?

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This is the first time I've heard this. Normally I think of the Encyclopedia Britannica as a reliable source of information, and they claim that Leonardo Fibonnaci was his original name. Would the references given at the end of the article be useful? Also – Todd Trimble Nov 2 '10 at 17:07
up vote 7 down vote accepted

From The Fabulous Fibonacci Numbers by A.S. Posamentier and I. Lehmann (Prometheus Books, New York (2007), pp. 17-18):

Leonardo Pisano - or Leonardo of Pisa, Fibonacci - his name as recorded in history, is derived from the Latin "filius Bonacci," or a son of Bonacci, but it may have been more likely derived from "de filius Bonacci," or family of Bonacci. He was born to Guglielmo (William) Bonacci and his wife in the port city of Pisa, Italy, around 1175, shortly after the start of construction of a famous bell tower, the Leaning Tower of Pisa.

The authors also indicate in a footnote that

it is unclear who first used the name Fibonacci; however, it seems to be attributed to Giovanni Gabriello Grimaldi (1757-1837) at around 1790 or to Pietro Cossali (1748-1815).

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Btw, maybe off topic, but actually here (Pisa) all buildings, old and new, are leaning. The Tower is just the most famous instance. Soft ground, and little ability in building construction. A small town with no right angles. The rest of Tuscany made jokes on that since Medieval times. – Pietro Majer Nov 2 '10 at 18:19

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