Etymologically
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porous

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Pronunciation

  • UK: /ˈpɔːɹəs/[1]
  • US: /ˈpɔɹəs/[1]

Etymology

It is inherited from Middle English porous, also porus and porose,[2] partly borrowed from Middle French poreux, Old French poros,[3][4][5][6] and partly borrowed from Medieval Latin porōsus,[3][4][7][2][8] formed from porus (“pore, passage”) and the suffix -ōsus.[3][7] The Medieval Latin word is recorded in British sources from about 1120, and the French one from about 1280.[3] The Latin noun is from Ancient Greek πόρος (póros, “passage, way; pore”),[4][5] from Proto-Indo-European *per- (“to lead, pass over”).[4][5] Compare porós, poroso and poroso.[3] It is related to pore.[4][5]

Earliest recorded meaning

Full of pores; letting fluids through: Barnhart dates the word to 1392;[9][8] the OED and the MED first find it in Trevisa's translation of Bartholomaeus Anglicus (before 1398), which says the tongue is porouse and hollow so that taste may reach the nerve more easily.[3][2]

Semantic evolution

The word began as a term of medicine and natural philosophy for anything full of small openings, such as skin, bone, earth or stone.[2][3] Johnson (1755) defined it as having small spiracles or passages, quoting Milton's "porous earth" from Paradise Lost.[10] A figurative sense, not retentive or not secure, letting people or information pass, appears in 1642, in Henry More,[3][4] and is the source of the modern use for borders and defences that are easy to get through.[11][7] In botany it has been used since 1861 of fruits that release their seeds through pores.[3]

Timeline

  • 1392 – full of pores (Barnhart's date); porosity from the same year.[8]
  • before 1398 – in Trevisa's translation of Bartholomaeus Anglicus.[3][2]
  • 1642 – figurative, not retentive, letting things pass.[3][4]
  • 1755 – Johnson defines it as having small spiracles or passages.[10]
  • 1861 – botany, of seeds released through pores.[3]

Meanings

Adjective

  1. Full of tiny pores or holes, so that water, air or other fluids can pass through; permeable: a porous clay pot.[11][7][3]
  2. (biology, geology) Having pores or vessels.[11][7]
  3. Easy to cross or get through; not secure: a porous frontier.[11][7][3]
  4. (botany) Taking place through pores, as when seeds are released through holes in a fruit.[3]

Word family

  • porously
  • porousness
  • microporous
  • nonporous
  • porosity
  • unporous

References

  1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
  3. ^ a b c d e f g h i j k l m n o Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  4. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  5. ^ a b c d The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
  6. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
  7. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  8. ^ a b c Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
  9. ^ Barnhart, Robert K., ed. (1995), The Barnhart Concise Dictionary of Etymology, New York: HarperCollins
  10. ^ a b Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
  11. ^ a b c d Collins English Dictionary (2023), Glasgow: HarperCollins