opacity

noun

opac·​i·​ty ō-ˈpa-sə-tē How to pronounce opacity (audio)
plural opacities
1
a
: 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)

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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The black box problem refers to the opacity of certain AI systems. David Paffenholz, Forbes, 7 Mar. 2025 This opacity hampers efforts to implement effective sustainability measures and underscores the need for industry-wide standards and greater transparency in reporting energy consumption and emissions. Monica Sanders, Forbes, 4 Mar. 2025 The lack of a standardized definition, the opacity of family office operations, and the differing methodologies employed all contribute to the discrepancies. Francois Botha, Forbes, 2 Mar. 2025 One big challenge in the bicycle industry is the unusual opacity of its supply chains. Jim Vinoski, Forbes, 21 Feb. 2025 See All Example Sentences for opacity

Word History

Etymology

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

First Known Use

1575, in the meaning defined at sense 1a

Time Traveler
The first known use of opacity was in 1575

Browse Nearby Words

Cite this Entry

“Opacity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/opacity. Accessed 17 Apr. 2025.

Kids Definition

opacity

noun
opac·​i·​ty ō-ˈpas-ət-ē How to pronounce opacity (audio)
plural opacities
: the quality or state of being opaque

Medical Definition

opacity

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

More from Merriam-Webster on opacity

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