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• gamma
  gamma

  noun

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

  noun

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

gamma

American  

[gam-uh] / ˈgæm ə /

noun

gammas plural

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

2. the consonant sound represented by this letter.

3. the third in a series of items.

4. Astronomy. Gamma, a star that is usually the third brightest of a constellation.

   The third brightest star in the Southern Cross is Gamma Crucis.

5. a unit of weight equal to one microgram.

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

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

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

9. Chiefly British. a grade showing that an individual student is in the third, or lowest, of three scholastic sections in a class.

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gamma ¹ British  

/ ˈɡæmə /

noun

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

2. the third highest grade or mark, as in an examination

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

4. 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

5. (modifier)

   1. involving or relating to photons of very high energy

      a gamma detector

   2. relating to one of two or more allotropes or crystal structures of a solid

      gamma iron

   3. 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

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Gamma ² British  

/ ˈɡæmə /

noun

1. (foll by the genitive case of a specified constellation) the third brightest star in a constellation

   Gamma Leonis

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Other Word Forms

Noun Inflected Forms

• gammas
  plural

Etymology

Origin of gamma

From the Greek word gámma

Example Sentences

See Examples For:

gamma Gamma gammas

Those elements can then release neutrons and gamma rays at different energy levels.

From Science Daily ● Jul. 28, 2026

Eradication was possible through the sterile insect technique, which uses gamma radiation to irradiate screwworm pupae and create sterile male flies.

From Los Angeles Times ● Jun. 6, 2026

MenthorQ has its own gamma index, and it has been reflecting some of the most stretched positioning seen over the past year.

From MarketWatch ● May 17, 2026

When gamma is this high, options dealers are consistently forced to buy shares, or index futures, to remain “delta neutral.”

From MarketWatch ● May 17, 2026

From gamma rays to radio waves, all are equally respectable bands of light.

From "Cosmos" by Carl Sagan

This past week, the Squeeze Metrics Gamma Index, which measures the dollar value of option dealers’ exposure to the call options they have sold to clients, hit its highest level since 2021.

From MarketWatch ● May 17, 2026

Gamma is essentially the rate of change in a stock option’s delta, and the delta is how an option price changes with changes in the underlying stock.

From Barron's ● Apr. 10, 2026

Jackson, who once managed the rapper and also previously worked at Apple Music, launched Gamma in 2023.

From The Wall Street Journal ● Jan. 28, 2026

Gamma rays coming from dark matter particle collisions would produce the same signal and have the same properties as those observed in the real-world, the researchers said -- though it's not definitive proof.

From Science Daily ● Oct. 18, 2025

I don’t remember how we got to the Gamma Alpha Psi house, but I’m sure if I drive around enough, I might find it.

From "Ask the Passengers" by A.S. King

A couple of hundred gammas per minute leak out through each hole, forming a pair of gamma-ray beams.

From Scientific American ● Feb. 14, 2013

To improve on the experiment, I need to beat down the accidental rate—in particular, the rate caused by gammas traveling straight from the sodium to the Geiger counter rather than scattering off the aluminum.

From Scientific American ● Feb. 14, 2013

The two gammas produced by the annihilation of an antielectron and electron are linearly polarized at right angles to each other, so they should scatter off the aluminum in perpendicular directions.

From Scientific American ● Feb. 14, 2013

On the opposite side of the fault from ground zero, the intensity of the magnetic field was found to have dropped by as much as eleven gammas after the test.

From Time Magazine Archive

I have remarked that the fylfot is sometimes described as being formed of four gammas conjoined in the centre.

From The Masculine Cross A History of Ancient and Modern Crosses and Their Connection with the Mysteries of Sex Worship; Also an Account of the Kindred Phases of Phallic Faiths and Practices by Anonymous