• synonyms


[pawr-uhs, pohr-]
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  1. full of pores.
  2. permeable by water, air, etc.
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Origin of porous

1350–1400; Middle English, variant of porose < Medieval Latin porōsus. See pore2, -ous
Related formspo·rous·ly, adverbpo·rous·ness, nounnon·po·rous, adjectivenon·po·rous·ness, nounun·po·rous, adjectiveun·po·rous·ness, noun

Synonyms for porous

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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for nonporous

tough, sturdy, solid, hard, unyielding, substantial, rigid, thick, stiff, compact, concentrated, condensed, set, refractory, concrete, hardened, close, heavy, solidified, compressed

Examples from the Web for nonporous

Historical Examples of nonporous

  • A porous separator allows more energy to be drawn from the battery than a nonporous one.

    The Automobile Storage Battery

    O. A. Witte

  • When a wooden case is used, jars made of rubber, or some other nonporous, acid-resisting material are necessary.

  • When the skin is ready to apply, coat this plaster cast with some nonporous modelling material.

British Dictionary definitions for nonporous


  1. not permeable to water, air, or other fluids
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  1. permeable to water, air, or other fluids
  2. biology geology having pores; poriferous
  3. easy to cross or penetratethe porous border into Thailand; the most porous defence in the league
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Derived Formsporously, adverbporousness, noun

Word Origin for porous

C14: from Medieval Latin porōsus, from Late Latin porus pore ²
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 nonporous



late 14c., "full of pores," from Old French poros (14c., Modern French poreux), from Medieval Latin porosus; or directly from Latin porus "an opening" (see pore (n.)). Figurative use from 1640s.

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Online Etymology Dictionary, © 2010 Douglas Harper

nonporous in Medicine


  1. Full of or having pores.
  2. Admitting the passage of gas or liquid through pores.
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Related formsporous•ness n.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

nonporous in Science


  1. Having many pores or other small spaces that can hold a gas or liquid or allow it to pass through.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.