opac·​i·​ty | \ ō-ˈpa-sə-tē How to pronounce opacity (audio) \
plural opacities

Definition of opacity

1a : obscurity of sense : unintelligibility
b : the quality or state of being mentally obtuse : dullness
2 : the quality or state of a body that makes it impervious to the rays of light broadly : the relative capacity of matter to obstruct the transmission of radiant energy
3 : an opaque spot in a normally transparent structure (such as the lens of the eye)

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Examples of opacity in a Sentence

the opacity of the glass Critics have noted the opacity of her writing style.
Recent Examples on the Web Many in China might hope that Li’s treatment and death would sound an alarm on the dangers of the Communist Party’s information control systems and opacity, but few will be optimistic that things will change. Tripti Lahiri, Quartz, "Questions swirl after China attempts to censor news of whistleblowing doctor’s death," 6 Feb. 2020 Layering and varying degrees of opacity give the works a sense of temporal texture and load the indeterminate with emotional heft. Leah Ollman, latimes.com, "Augustus Thompson paints life passing by with elegiac mystery," 10 June 2019 Because of their opacity, algorithms can privilege or discriminate without their creators designing them to do so, or even being aware of it. Sidney Fussell, The Atlantic, "Algorithms Are People," 18 Sep. 2019 Annapurna Pictures Bernadette’s opacity as a character is actually fitting for a movie about a woman who’s become a mystery to everyone, including herself. Alissa Wilkinson, Vox, "Where’d You Go, Bernadette," 16 Aug. 2019 But the opacity has raised concerns about fairness and transparency. Catherine Matacic, Science | AAAS, "This U.S. lawmaker wants greater scrutiny of algorithms used in criminal trials," 23 Sep. 2019 The trouble for investors is that this opacity may not last much longer. Charley Grant, WSJ, "Skies Darken for Drug Middlemen," 7 Aug. 2018 After spending so much time with Janice, who is serene and twinkly eyed and maddeningly committed to opacity in conversation, anybody might find Lynne's belligerence refreshing. Margaret Gray, latimes.com, "'An Undivided Heart' on stage is 'Spotlight' meets 'A Civil Action,' with a dash of Tammy Wynette," 9 Apr. 2018 The lack of transparency on the economics of the music industry and how the opacity negatively affects creators or artists. Billboard Staff, Billboard, "Revealed: Billboard's 2019 Top Music Lawyers Led by BTS Counsel Debbie White of Loeb & Loeb," 26 Aug. 2019

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

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First Known Use of opacity

1575, in the meaning defined at sense 1a

History and Etymology for opacity

Middle French opacité shadiness, from Latin opacitat-, opacitas, from opacus shaded, dark

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Time Traveler for opacity

Time Traveler

The first known use of opacity was in 1575

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Statistics for opacity

Last Updated

16 Feb 2020

Cite this Entry

“Opacity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/opacity. Accessed 25 Feb. 2020.

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More Definitions for opacity


How to pronounce opacity (audio)

English Language Learners Definition of opacity

: the quality of a material that does not allow light to pass through it : the quality of being opaque
formal : the quality of being difficult to understand or explain


opac·​i·​ty | \ ō-ˈpas-ət-ē How to pronounce opacity (audio) \
plural opacities

Medical Definition of opacity

1 : the quality or state of a body that makes it impervious to the rays of light broadly : the relative capacity of matter to obstruct by absorption or reflection the transmission of radiant energy (as X-rays, infrared radiation, or sound)
2 : an opaque spot in a normally transparent structure (as the lens of the eye)

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