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• fermi
  fermi

  noun

  a unit of length, 10− 15 m, used in measuring nuclear distances. F
• Fermi
  Fermi

  noun

  Enrico 1901–54, Italian physicist, in the U.S. after 1939: Nobel Prize 1938.

fermi

¹ American  

[fur-mee, fer-mee] / ˈfɜr mi, ˈfɛr mi /

noun

Physics.

1. a unit of length, 10− 15 m, used in measuring nuclear distances. F

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Fermi ² American  

[fur-mee, fer-mee] / ˈfɜr mi, ˈfɛr mi /

noun

1. Enrico 1901–54, Italian physicist, in the U.S. after 1939: Nobel Prize 1938.

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Fermi ¹ British  

/ ˈfɜːmɪ, ˈfɛrmi /

noun

1. Enrico (enˈriːko). 1901-54, Italian nuclear physicist, in the US from 1939. He was awarded a Nobel prize for physics in 1938 for his work on radioactive substances and nuclear bombardment and headed the group that produced the first controlled nuclear reaction (1942)

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fermi ² British  

/ ˈfɜːmɪ /

noun

1. a unit of length used in nuclear physics equal to 10 ^–15 metre

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Fermi Scientific  

/ fĕr′mē /

1. Italian-born American physicist who won a 1938 Nobel Prize for his research on neutrons. In 1942, with Leo Szilard, Fermi built the world's first nuclear reactor. He also discovered over 40 new isotopes, including the element fermium, which is named for him.

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Etymology

Origin of fermi

Named after E. Fermi

Example Sentences

See Examples For:

fermi Fermi

First, we must calculate the time Δt that the pion exists, given that the distance it travels at nearly the speed of light is about 1 fermi.

From Textbooks ● Aug. 12, 2015

Why is it that the electron seems to have no size other than its wavelength, while the proton and neutron are about 1 fermi in size?

From Textbooks ● Aug. 12, 2015

I reserve for you some canti fermi and antiphons, which I wrote down at the time, and my little book describes the order of the various services and the meaning of the different ceremonies.

From Letters of Felix Mendelssohn Bartholdy from Italy and Switzerland by Felix Mendelssohn-Bartholdy

Fermi also said Hillcore Energy Capital will build, own and operate 2.6 gigawatts of power generation—mostly natural gas with some solar and battery storage—at Project Matador.

From The Wall Street Journal ● Aug. 13, 2026

Fermi wouldn’t be required to commit money or issue debt to build the plant but would have the option to buy it in a decade.

From The Wall Street Journal ● Aug. 13, 2026

Fermi announces a $6.5 billion lease contract with AI cloud provider TensorWave.

From Barron's ● Aug. 11, 2026

"In certain directions inside the crystal, the nodal lines intersect and cross the Fermi energy where electrons can move freely," explains Sánchez-Barriga.

From Science Daily ● Jun. 5, 2026

Plainly skeptical but unwilling to engage in a colloquy with a wheedling Teller, Fermi pleaded that he was too tired from the flight to give him a hearing, much less a commitment.

From "Big Science" by Michael Hiltzik