1 [grey]
adjective, grayer, grayest.
of a color between white and black; having a neutral hue.
dark, dismal, or gloomy: gray skies.
dull, dreary, or monotonous.
having gray hair; gray-headed.
pertaining to old age; mature.
Informal. pertaining to, involving, or composed of older persons: gray households.
old or ancient.
indeterminate and intermediate in character: The tax audit concentrated on deductions in the gray area between purely personal and purely business expenses.
any achromatic color; any color with zero chroma, intermediate between white and black.
something of this color.
gray material or clothing: to dress in gray.
an unbleached and undyed condition.
(often initial capital letter) a member of the Confederate army in the American Civil War or the army itself. Compare blue ( def 5 ).
a horse of a gray color.
a horse that appears white but is not an albino.
verb (used with object), verb (used without object)
to make or become gray.
Also, grey.

before 900; Middle English; Old English grǣg; cognate with German grau

grayly, adverb
grayness, noun
ungrayed, adjective Unabridged


2 [grey]
noun Physics.
the standard unit of absorbed dose of radiation (such as x-rays) in the International System of Units (SI), equal to the amount of ionizing radiation absorbed when the energy imparted to matter is 1 J/kg (one joule per kilogram). Abbreviation: Gy
Compare rad.

1975; named in honor of Louis Harold Gray (1905–65), English radiobiologist


Asa [ey-suh] , 1810–88, U.S. botanist.
Robert, 1755–1806, U.S. explorer and sea captain: discovered the Columbia River.
Thomas, 1716–71, English poet. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
gray1 (ɡreɪ)
adj, —n, —vb
a variant spelling (now esp US) of grey

gray2 (ɡreɪ)
Gy the derived SI unit of absorbed ionizing radiation dose or kerma equivalent to an absorption per unit mass of one joule per kilogram of irradiated material. 1 gray is equivalent to 100 rads
[C20: named after Louis Harold Gray (1905--65), English physicist]

Gray (ɡreɪ)
1.  Simon (James Holiday). born 1936, British writer: his plays include Butley (1971), The Common Pursuit (1988), Life Support (1997), and Japes (2001)
2.  Thomas. 1716--71, English poet, best known for his Elegy written in a Country Churchyard (1751)

grey or gray (ɡreɪ)
1.  of a neutral tone, intermediate between black and white, that has no hue and reflects and transmits only a little light
2.  greyish in colour or having parts or marks that are greyish
3.  dismal or dark, esp from lack of light; gloomy
4.  neutral or dull, esp in character or opinion
5.  having grey hair
6.  of or relating to people of middle age or above: grey power
7.  ancient; venerable
8.  (of textiles) natural, unbleached, undyed, and untreated
9.  any of a group of grey tones
10.  grey cloth or clothing: dressed in grey
11.  an animal, esp a horse, that is grey or whitish
12.  to become or make grey
[Old English grǣg; related to Old High German grāo, Old Norse grar]
gray or gray
[Old English grǣg; related to Old High German grāo, Old Norse grar]
'greyish or gray
'grayish or gray
'greyly or gray
'grayly or gray
'greyness or gray
'grayness or gray

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Word Origin & History

O.E. græg (Mercian grei), from P.Gmc. *græwyaz (cf. O.N. grar, O.Fris. gre, Du. graw, Ger. grau), from PIE *ghreghwos, but no certain cognates outside Gmc. The distinction between British grey and U.S. gray developed 20c. Gray as figurative for "Southern troops in the U.S. Civil War" is first
recorded 1863, in reference to their uniform color.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

gray (grā)
Abbr. Gy
A unit for a specific absorbed dose of radiation equal to 100 rads.

Gray (grā), Henry. 1825?-1861.

British anatomist whose work Anatomy, Descriptive and Surgical (1858), known as Gray's Anatomy, remains a standard text.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
gray   (grā)  Pronunciation Key 
The SI derived unit used to measure the energy absorbed by a substance per unit weight of the substance when exposed to radiation. One gray is equal to one joule per kilogram, or 100 rads. The gray is named after British physicist Louis Harold Gray (1905-1965).
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Computing Dictionary

Gray definition

A parser generator written in Forth by Martin Anton Ertl Gray takes grammars in an extended BNF and produces executable Forth code for recursive descent parsers. There is no special support for error handling. Version 3 runs under Tile Forth Release 2 by Mikael Patel.
The Free On-line Dictionary of Computing, © Denis Howe 2010
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American Heritage
Idioms & Phrases


In addition to the idioms beginning with gray, also see get gray hair from.

The American Heritage® Dictionary of Idioms by Christine Ammer.
Copyright © 1997. Published by Houghton Mifflin.
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Encyclopedia Britannica


unit of absorbed dose of ionizing radiation, defined in the 1980s by the International Commission on Radiation Units and Measurements. One gray is equal approximately to the absorbed dose delivered when the energy per unit mass imparted to matter by ionizing radiation is one joule per kilogram. As a unit of measure, the gray is coherent with the units of measure in the International System of Units (SI). The gray replaced the rad, which was not coherent with the SI system. One gray equals 100 rads

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences for gray
Such familiarity has inspired a long list of colloquial names for the gray jay.
In gray jays, however, nonbreeders do not help their parents to raise younger
The gray version, which was the first, was the rarer of the two.
The pallium is a layer of gray matter that lies on the surface of the forebrain.
Idioms & Phrases
Image for gray
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