the third letter of the Greek alphabet (Γ, γ).
the consonant sound represented by this letter.
the third in a series of items.
Astronomy. Gamma, 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.
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 energy
a gamma detector
relating to one of two or more allotropes or crystal structures of a solid
gamma 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
From the Greek word gámma
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
"Observing gamma rays from supernovae will give us a new way to explore their inner workings."
From Science Daily • May 27, 2026
Inside this nebula, particle interactions can generate gamma rays in several ways.
From Science Daily • May 27, 2026
“You have a massive gamma squeeze going on right now in Micron,” said Michael Kramer of Mott Capital Management.
From MarketWatch • May 26, 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
Beyond the ultraviolet is the X-ray part of the spectrum, and beyond the X- rays are the gamma rays.
From "Cosmos" by Carl Sagan
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
