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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

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

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

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 Mendelssohn-Bartholdy, Felix

At nearly the same time, NASA's Fermi Gamma-ray Space Telescope detected several gamma-ray bursts coming from the same region of the sky.

From Science Daily ● Jun. 26, 2026

Former Fermi CFO Miles Everson’s compensation in 2025 topped $134 million, the bulk of which was stock awards valued at over $132 million, according to a regulatory filing.

From The Wall Street Journal ● Jun. 23, 2026

NASA's Fermi Gamma-ray Space Telescope may have finally uncovered what powers some of the brightest stellar explosions ever observed.

From Science Daily ● May 27, 2026

The team also tested whether the proposed blazar population would produce too many gamma rays compared with the known extragalactic gamma ray background measured by Fermi.

From Science Daily ● May 24, 2026

Sitting in on a Berkeley seminar given by a group of Oppenheimer students in 1940, Fermi found himself unable to follow the mumbled discussion.

From "Big Science" by Michael Hiltzik