penetrable

Etymology

It is inherited from Middle English penetrable,^[2] borrowed from Middle French pénétrable and directly borrowed from Latin penetrābilis (“capable of penetrating; capable of being penetrated”).^[3][4] Etymonline and Merriam-Webster Unabridged name only the Latin word,^[5][6] while Klein and Johnson also give French.^[7][8] The Latin adjective is formed from penetrō (“to get into”) and -bilis.^[3][6] The verb comes from penitus (“interior, inmost”), on the model of intrō (“to enter”) beside intus (“within”),^[3] and is related to penus (“provisions; innermost part of a house”).^[6] Compare Spanish penetrable and Italian penetrabile, both from the 14th century.^[3]

Earliest recorded meaning

Capable of penetrating, penetrating: about 1425, in Lydgate's Troy Book, of balm running through pipes in the neck and head,^[3][2] though the Middle English Dictionary thinks that this first quotation might also mean "capable of being penetrated".^[2]

Semantic evolution

The Latin adjective could be active or passive, and English took the active sense first; it died out by 1598 in the OED,^[3] by the mid-17th century in the Shorter Oxford, which quotes Henry More.^[4] The passive sense, the only one left, is recorded from 1538, in Elyot's dictionary,^[3][6] The figurative sense appears in Shakespeare's Lucrece (1594),^[3][5] and Richard III has "penetrable to your kind entreaties".^[4][8] Johnson (1755) gives both of the living senses, the second as open to moral or intellectual impression.^[8]

Timeline

• c. 1425 – capable of penetrating; penetrating (obsolete by 1598).^[3][2]
• 1538 – capable of being pierced or entered.^[3][6]
• 1594 – figurative, open to reason or understanding; susceptible.^[3]
• 1658 – noun, a penetrable body or substance (rare and obsolete).^[3]

Meanings

Adjective

1. Able to be pierced or entered, or allowing passage or sight through; permeable: The hedge was penetrable at only one gap.^[6][3][4]
2. Able to be understood by thought or reasoning; open to ideas or feelings; susceptible.^[3][4][8]
3. (obsolete, c. 1425–1598) Capable of penetrating; penetrative.^[3][4][2]

Word family

• penetrability
• penetrably
• nonpenetrable
• unpenetrable

Related words

• penetrate
• impenetrable

References

1. ^ 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 Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ a b Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
7. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
8. ^ a b c d Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.