[ oh-pas-i-tee ]
/ oʊˈpæs ɪ ti /

noun, plural o·pac·i·ties.

Nearby words

  1. op. cit.,
  2. opa,
  3. opa-locka,
  4. opacification,
  5. opacify,
  6. opacus,
  7. opafication,
  8. opah,
  9. opal,
  10. opal glass

Origin of opacity

First recorded in 1550–60, opacity is from the Latin word opācitās shade. See opaque, -ity

Related formsnon·o·pac·i·ty, noun, plural non·o·pac·i·ties.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for opacities

British Dictionary definitions for opacities


/ (əʊˈpæsɪtɪ) /

noun plural -ties

the state or quality of being opaque
the degree to which something is opaque
an opaque object or substance
obscurity of meaning; unintelligibility
physics photog the ratio of the intensity of light incident on a medium, such as a photographic film, to that transmitted through the medium
logic philosophy the property of being an opaque context
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for opacities



1550s, "darkness of meaning, obscurity," from French opacité, from Latin opacitatem (nominative opacitas) "shade, shadiness," from opacus "shaded, dark, opaque" (see opaque). The literal sense "condition of being impervious to light" first recorded 1630s.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for opacities


[ ō-păsĭ-tē ]


The quality or state of being opaque.
An opaque or nontransparent area, as of the cornea.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.