from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun The state or property of being porous.
  • noun A structure or part that is porous.
  • noun The ratio of the volume of all the pores in a material to the volume of the whole.

from The Century Dictionary.

  • noun The state or quality of being porose, porous, or pervious; perforation.
  • noun A pore or perforation.

from the GNU version of the Collaborative International Dictionary of English.

  • noun The quality or state of being porous; -- opposed to density.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun uncountable The state of being porous
  • noun countable A measure of how porous a material is; the ratio of the volume of pores to the total volume

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun the property of being porous; being able to absorb fluids


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English porosite, from Old French, from Medieval Latin porōsitās, from porōsus, porous; see porous.]


    Sorry, no example sentences found.


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  • porosity/porousness. what are the differences in usage?

    September 15, 2008

  • I think porosity can always be used in place porousness, but not vice versa. One can say "a porosity in the surface marred the finish", which means that a particular area was flawed. But one would say "The porousness of the surface marred the finish", meaning that the whole surface was flawed.

    September 15, 2008

  • that was illuminating, thank you! :-)

    September 15, 2008