|A.K.A.||Nicolaus Fuss, Nicolaus von Fuss, Nikolai Fuss|
|Countries||Switzerland Russian Empire|
|Occupations||Mathematician University teacher|
|Birth||29 January 1755 (Basel)|
|Death||4 January 1826 (Saint Petersburg)|
Nicolas Fuss (29 January 1755 – 4 January 1826), also known as Nikolai Fuss, was a Swiss mathematician, living most of his life in Imperial Russia.
Fuss was born in Basel, Switzerland. He moved to Saint Petersburg to serve as a mathematical assistant to Leonhard Euler from 1773–1783, and remained there until his death. He contributed to spherical trigonometry, differential equations, the optics of microscopes and telescopes, differential geometry, and actuarial science. He also contributed to Euclidean geometry, including the problem of Apollonius.
In 1797, he was elected a foreign member of the Royal Swedish Academy of Sciences. From 1800–1826, Fuss served as the permanent secretary to the Academy of Sciences in St. Petersburg. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1812. He died in St. Petersburg.
Nicolas Fuss was married to Albertine Benedikte Philippine Luise Euler (1766-1822). Albertine Euler was the daughter of Leonhard Euler's eldest son Johann Albrecht Euler (1734-1800) and his wife Anna Sophie Charlotte Hagemeister. Pauline Fuss, a daughter of Nicolas and Albertine, married Russian chemist Genrikh Struve.