gamma

1 of 2

noun

gam·​ma ˈga-mə 

plural gammas

1

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

2

: something or someone designated with the name gamma or the Greek letter γ especially denoting the third in position, order, or class

gamma hydroxybutyrate

3

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

4

: a unit of magnetic flux density equal to one nanotesla

5

: gamma ray

gamma counter

6

: microgram

gamma

2 of 2

adjective

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

Examples of gamma in a Sentence

Recent Examples on the Web

Noun

Reid’s mega label, in partnership with Larry Jackson’s gamma. —Christopher Claxton, Billboard, 17 Mar. 2025

Saez and his team found that meditation practice caused modulations in the beta and gamma waves in the amygdala and hippocampus of these novice meditators. —Avery Hurt, Discover Magazine, 17 Mar. 2025

Adjective

The company expects these programs to lead to full a gamma version and full production runs by the end of 2024. —IEEE Spectrum, 31 Jan. 2023

And the worldwide shortage of gamma ferric oxide has brought tape production to a crawl. —David Grossman, Popular Mechanics, 11 Oct. 2019

Word History

Etymology

Noun

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

Adjective

attributive use of gamma entry 1

First Known Use

Noun

15th century, in the meaning defined at sense 1

Adjective

1834, in the meaning defined at sense 1

Phrases Containing gamma

• gamma-aminobutyric acid
• gamma camera
• gamma globulin
• gamma hydroxybutyrate
• gamma interferon
• gamma radiation
• gamma ray
• gamma ray burst
• interferon gamma

Rhymes for gamma

• grama
• gramma
• diorama
• panorama
• trichogramma

Kids Definition

gamma

noun

gam·​ma

ˈgam-ə

: the third letter of the Greek alphabet

—Γ or γ

Medical Definition

gamma

1 of 2 noun

gam·​ma ˈgam-ə 

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 sense 1

gamma

2 of 2 adjective

variants or γ-

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