gamma

play

noun gam·ma \ ˈga-mə \

Definition of gamma

1 :the 3rd letter of the Greek alphabet — see Alphabet Table

2 :the degree of contrast of a developed photographic image or of a video image

3 :a unit of magnetic flux density equal to one nanotesla

4 :gamma ray

gamma counter

5 :microgram

See gamma defined for English-language learners

See gamma defined for kids

Recent Examples of gamma from the Web

The love-him-or-loathe him funnyman was the patron saint of every gamma geek who aspired to be an alpha male.

— carrie rickey, Philly.com, "Jerry Lewis, America's funnyman, dies at 91," 20 Aug. 2017
Researchers want to know more about gamma ray bursts to better understand the universe and its origins.

— carrie wells, baltimoresun.com, "University of Maryland scientists observe rare gamma ray burst," 11 Aug. 2017
Currently, there are more than three dozen orbiting telescopes at work, observing the cosmos in multiple wavelengths, including the visible, ultraviolet, x-ray and gamma ray.

— jeffrey kluger, Time, "As Eclipse Watchers Look to the Sky, a New Age of Telescopes Is Dawning," 1 Aug. 2017
If confirmed, the findings would offer the first solid clue as to what caused Earth's first mass extinction—hypothesized to be the result of everything from toxic metals unleashed in the oceans to radiation from a distant gamma-ray burst.

— shannon hall, Scientific American, "Volcanoes May Have Triggered the Last Unexplained Mass Extinction," 24 July 2017
Other options: exploding stars known as supernovae or gamma ray bursts, highly energetic explosions in outer space.

— giorgia guglielmi, Science | AAAS, "This is what it would take to kill all life on Earth," 14 July 2017
The Incredible Hulk roller coaster shoots out of the gamma-ray accelerator, turns upside down and dives.

— marjie lambert, miamiherald, "A volcano and a 3D race with Jimmy Fallon," 16 June 2017
A second point of contention is how quickly the scope can shift from a wide-field survey mode to one that would focus on transient phenomena, such as gamma ray bursts and supernovae.

— dennis normile, Science | AAAS, "Spat threatens China’s plans to build world’s largest telescope," 14 June 2017
The flare-up occurred when the star's massive, twisting magnetic field ripped open its crust, releasing an explosion of gamma rays.

— National Geographic, "Bizarre Black Holes Revealed by New Space-Time Ripples," 1 June 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'gamma.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of gamma

Middle English, borrowed from Latin, borrowed from Greek gȧmma, borrowed from Phoenician *gaml-, perhaps with the original sense "throwing stick"

NEW! Time Traveler

First Known Use: 15th century

See Words from the same year

gamma

adjective

Definition of gamma

1 :of, relating to, or being one of three or more closely related chemical substances

2 :third in position in the structure of an organic molecule from a particular group or atom —symbol γ

Recent Examples of gamma from the Web

The machine uses gamma rays to shrink brain tumors as an alternative to open-skull surgery, Andy Marso reports.

— max londberg, kansascity.com, "Morning Rush: Chiefs fire GM John Dorsey, roaches at area food operations, Big Slick," 23 June 2017
World View has since carried other experiments, including a gamma ray detector and a remote-sensing system.

— adam mann, Science | AAAS, "Commercial balloons in the stratosphere could monitor hurricanes and scan for solar storms," 22 June 2017
These are caused by the collapse of a massive star into a black hole or the collision of a pair of the dense stellar remnants called neutron stars, and squirt gamma rays but only in one direction.

— dennis overbye, New York Times, "A Mysterious Flash From a Faraway Galaxy," 31 Mar. 2017
The collective radiation from all of these hydrogen atom collisions, in the form of light, heat, gamma rays, and X-rays, slowly makes its way to the outer layer of a star.

— mike lynch / sky watch, Twin Cities, "Sky Watch: Inside the violent core of a star (and our sun)," 18 Mar. 2017
In the 1960s, when gamma-ray bursts were first detected, scientists didn’t know what to make of them.

— National Geographic, "Astronomers Discover a New Kind of Radio Blast From Space," 2 Mar. 2016

Origin and Etymology of gamma

attributive use of ¹gamma

NEW! Time Traveler

First Known Use: 1834

See Words from the same year

GAMMA Defined for English Language Learners

gamma

play

noun

Definition of gamma for English Language Learners

: the third letter of the Greek alphabet

Medical Dictionary

gamma

play

noun gam·ma \ ˈgam-ə \

medical Definition of gamma

1 :the third letter of the Greek alphabet —symbol Γ or γ

2 :a unit of magnetic flux density equal to one nanotesla

3 :gamma ray —usually used as the attributive form of gamma ray

gamma counter

4 :microgram 1

gamma

adjective

variants: or γ-

medical Definition of gamma

1 :of or relating to one of three or more closely related chemical substances

the gamma chain of hemoglobin

γ-yohimbine

—used somewhat arbitrarily to specify ordinal relationship or a particular physical form and especially one that is allotropic, isomeric, or stereoisomeric (as in gamma benzene hexachloride)

2 :third in position in the structure of an organic molecule from a particular group or atom; also :occurring at or having a structure characterized by such a position

γ-hydroxy acids

3 of streptococci :producing no hemolysis on blood agar plates

Learn More about gamma

See words that rhyme with gamma Britannica.com: Encyclopedia article about gamma

Seen and Heard

What made you want to look up gamma? Please tell us where you read or heard it (including the quote, if possible).

show

gamma

Definition of gamma

People Are Reading

Recent Examples of gamma from the Web

Origin and Etymology of gamma

gamma

Definition of gamma

Recent Examples of gamma from the Web

Origin and Etymology of gamma

Phrases Related to GAMMA

Related Phrases

GAMMA Defined for English Language Learners

gamma

Definition of gamma for English Language Learners

Medical Dictionary

gamma

medical Definition of gamma

gamma

medical Definition of gamma

Learn More about gamma

Seen and Heard

Love words? Need even more definitions?

Love words? Need even more definitions?

Words at Play

Ask the Editors

Word Games

Let's Talk 'Tea'

These Are Fighting Words

Merriam-Webster's New Words Quiz—Fall 2017 Edition!

Trending: Ivanka: "An 'Otherwise' Incredible Day"

Words of the Year: 1066