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 Where opacity is required to shield mechanical rooms, there is white Texas shellstone, imprinted with the state’s fossil history. Mark Lamster, Dallas News, 6 May 2021 When Facebook was asked to explain itself, its responses ranged from opacity to baffling incoherence. Andrew Marantz, The New Yorker, 5 May 2021 Light reflectivity varies wildly based on the material that photons are bouncing off including the texture, opacity and color among other factors. Sam Abuelsamid, Forbes, 12 Apr. 2021 The distinction isn’t between objectivity and bias; it’s between transparency and opacity. Judy Berman, Time, 8 Mar. 2021 The move deepened a mystery encompassing the pernicious spread of a deadly pathogen, an intricate epidemiological puzzle, the opacity of a totalitarian system and the bitter overtones of a superpower rivalry. Stephen Collinson, CNN, 27 May 2021 With the opacity of market pricing, Bellwether Coffee is turning to a new tool, the Verified Living Income Indicator, to determine sustainable pricing for smallholder coffee farmers, and adjust their pricing in contracts accordingly. Shayna Harris, Forbes, 11 May 2021 Such opacity helped to worsen the 2008 financial crisis and regulators have introduced a vast new body of rules governing the assets since then. Fortune, 29 Mar. 2021 The opacity of other people, the difficulty of making definitive judgments about them, is another Murakami concern. BostonGlobe.com, 1 Apr. 2021

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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Learn More About opacity

Time Traveler for opacity

Time Traveler

The first known use of opacity was in 1575

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Statistics for opacity

Last Updated

12 Jun 2021

Cite this Entry

“Opacity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/opacity. Accessed 18 Jun. 2021.

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More Definitions for opacity



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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