aperture

Etymology

It is inherited from Middle English aperture,^[2][3][4] borrowed from Latin apertūra (“an opening”),^{[5][3][6][7][8]} from apertus (“opened, open”), the past participle of aperiō (“to open, uncover”),^[3][6][4][9] with the noun suffix -ūra, English -ure.^[5][7][8] Collins calls the Latin noun Late Latin,^[10] and Barnhart allows that it may have come through Middle French aperture.^[11] Etymonline and the American Heritage Dictionary trace the Latin verb to a compound Proto-Indo-European *ap-wer-yo-, of *ap- (“off, away”) and *wer- (“to cover”);^[3][6] Merriam-Webster likewise takes it from a prefix akin to ab (“from”) and an assumed verb meaning "to cover", related to weir.^[4]

Earliest recorded meaning

An opening, and the making of an opening: about 1425, in the Middle English translation of Chauliac's surgery, which glosses the word "opnyng" and speaks of treating a swelling of the head by aperture.^[2][3]

Semantic evolution

The OED, in an entry not revised since 1885, records the word only from 1649, when Jeremy Taylor used it for the opening up of something intricate, a rare sense soon lost;^[5][11] the act of opening is recorded from 1669 to 1709, in Holder's Elements of Speech first.^[5][12] Johnson (1755) gave both "the act of opening", quoting Holder, and "an open place".^[13] The concrete sense, an opening between solid parts, a gap or hole, dates from 1661,^[5][12] and was applied to the mouth of a mollusc's shell by 1794.^[12] In optics the word has meant, since 1665, the space through which light passes in an instrument such as a telescope, even where there is no material hole,^[5][3] and later the diameter of that space;^[3][10] in photography it is the opening of a lens that lets light through.^[4] An aperture sight on a rifle is recorded from before 1884.^[5]

Timeline

• c. 1425 – an opening; the act of opening, in Chauliac.^[2][3]
• 1649 – the opening up of something intricate (obsolete).^[5][11]
• 1661 – a gap, cleft or hole.^[5][12]
• 1665 – optics, the space through which light passes.^[5][3]
• 1669 – the act of opening (obsolete by 1709).^[5]
• 1794 – the mouth of a mollusc's shell.^[12]
• before 1884 – the opening in a rifle sight.^[5]

Meanings

Noun

1. An opening, such as a hole, gap, crack or slit: Light came in through a narrow aperture in the shutters.^[10][4][5]
2. (optics, photography) The opening in a lens or other optical instrument that controls how much light or other radiation passes through, often adjustable.^[10][4][5]
3. The diameter of such an opening.^[10][3]
4. (zoology) The mouth of the shell of a mollusc.^[5]
5. (obsolete, 1669–1709) The act of opening.^[5][4][8]

Word family

• apertural
• apertured
• apertometer
• aperture-priority

Related words

• aperient
• aperitive

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c 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 Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ a b c d e f g h i j k l m n o p Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
6. ^ a b c The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
7. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
8. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
9. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
10. ^ a b c d e Collins English Dictionary (2023), Glasgow: HarperCollins
11. ^ a b c Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
12. ^ a b c d e Kay, Christian; Roberts, Jane; Samuels, Michael; Wotherspoon, Irené, eds. (2009), Historical Thesaurus of the Oxford English Dictionary, Oxford: Oxford University Press; online edition (2024)
13. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.