gamma

[ gam-uh ]

/ ˈgæm ə /

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noun

the third letter of the Greek alphabet (Γ, γ).

the consonant sound represented by this letter.

the third in a series of items.

Gamma, Astronomy. a star that is usually the third brightest of a constellation: The third brightest star in the Southern Cross is Gamma Crucis.

a unit of weight equal to one microgram.

Physics. a unit of magnetic field strength, equal to 10−5 gauss.

Photography. a measure of the degree of development of a negative or print.

Television. an analogous numerical indication of the degree of contrast between light and dark in the reproduction of an image in television.

Chiefly British. a grade showing that an individual student is in the third, or lowest, of three scholastic sections in a class.Compare alpha (def. 7), beta (def. 8).

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Question 1 of 6

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Origin of gamma

From the Greek word gámma

Words nearby gamma

gamine, gaminess, gaming, gaming platform, gaming table, gamma, gamma-aminobutyric acid, gamma angle, gamma-benzene hexachloride, gamma camera, gamma carotene

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use gamma in a sentence

The highest-energy gamma ray carried about 957 trillion electron volts.
The Milky Way’s newfound high-energy glow hints at the secrets of cosmic rays|Emily Conover|February 2, 2021|Science News
The quake led the magnetar to release a blob of plasma that sped away at nearly the speed of light, emitting gamma rays and X-rays as it went.
The first magnetar flare detected from another galaxy was tracked to its home|Lisa Grossman|January 19, 2021|Science News
Prescription Aklief cream, the first new retinoid product in more than 20 years, selectively targets RAR gamma, the most common retinoic acid receptor on the skin.
The 9 top health and medicine breakthroughs of 2020|Claire Maldarelli|December 2, 2020|Popular-Science
When we injected the combination of TNF and interferon gamma, mice are dead like flies.
How two immune system chemicals may trigger COVID-19’s deadly cytokine storms|Tina Hesman Saey|October 30, 2020|Science News

In fact, the change can happen when gamma rays strike many different kinds of photons.
The Hidden Magnetic Universe Begins to Come Into View|Natalie Wolchover|July 2, 2020|Quanta Magazine
Well, maybe it was a gamma-ray burst, or maybe it was something else, cautioned some others.
The Gamma-Ray Burst That Wasn’t|Matthew R. Francis|June 1, 2014|DAILY BEAST
The name is descriptive: they are extremely intense bursts of gamma rays, the highest energy form of light.
The Gamma-Ray Burst That Wasn’t|Matthew R. Francis|June 1, 2014|DAILY BEAST
Only gamma rays can do it, since all other forms of light are too low-energy.
We Can Create Matter from Light?!|Matthew R. Francis|May 20, 2014|DAILY BEAST
When the gamma rays enter the sleeve, they interact with that photon gas, annihilating into electron-positron pairs.
We Can Create Matter from Light?!|Matthew R. Francis|May 20, 2014|DAILY BEAST
He created his own agency, Gamma, in 1966, though he later left to join Magnum.
Photographer Raymond Depardon Captures the ‘Sweet Moments’|Sarah Moroz|November 15, 2013|DAILY BEAST
They combine the square and the cross, while the head and bill of the bird form the gamma indicative of the Swastika.
The Swastika|Thomas Wilson
I've got a little rocking-chair down in gamma's room—used to be cousin Efan's.
The Open Question|Elizabeth Robins
Little children say pease for please, gamma or granma for grandma, dess for dress, tocking for stocking.
The Sounds of Spoken English|Walter Rippmann
It certainly can't be anything less than gamma rays and probably even of greater frequency.
Islands of Space|John W Campbell
Radioactive atoms almost always decay by emitting negatively charged beta particles usually accompanied by gamma rays.
The Atomic Fingerprint|Bernard Keisch

British Dictionary definitions for gamma (1 of 2)

gamma

/ (ˈɡæmə) /

noun

the third letter in the Greek alphabet (Γ, γ), a consonant, transliterated as g. When double, it is transcribed and pronounced as ng

the third highest grade or mark, as in an examination

a unit of magnetic field strength equal to 10 –5 oersted. 1 gamma is equivalent to 0.795 775 × 10 –3 ampere per metre

photog television the numerical value of the slope of the characteristic curve of a photographic emulsion or television camera; a measure of the contrast reproduced in a photographic or television image

(modifier)

involving or relating to photons of very high energya gamma detector
relating to one of two or more allotropes or crystal structures of a solidgamma iron
relating to one of two or more isomeric forms of a chemical compound, esp one in which a group is attached to the carbon atom next but one to the atom to which the principal group is attached

Word Origin for gamma

C14: from Greek; related to Hebrew gīmel third letter of the Hebrew alphabet (probably: camel)

British Dictionary definitions for gamma (2 of 2)

Gamma

/ (ˈɡæmə) /

noun

(foll by the genitive case of a specified constellation) the third brightest star in a constellationGamma Leonis

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for gamma (1 of 2)

The Greek letter gamma. Entries beginning with this character are alphabetized under gamma.

Medical definitions for gamma (2 of 2)

gamma

[ găm′ə ]

The third letter of the Greek alphabet.

The third item in a series or system of classification.

The third position from a designated carbon atom in an organic molecule at which an atom or a radical may be substituted.

A unit of magnetic field strength equal to one hundred thousandth (105) of an oersted.

A unit of mass equal to one millionth (106) of a gram.

adj.

Relating to or being the atom or radical group that is in the third position relative to the functional group of atoms in an organic molecule.

Relating to or characterizing a polypeptide chain that is one of five types of heavy chains that may be present in immunoglobins.