opaque

Etymology

It was first inherited from Middle English opake,^[2][3][4] borrowed from Latin opācus (“shaded, shady, dark”).^[5][3][6][2] The OED treats that first record as an isolated early borrowing, and the later use as partly borrowed from Middle French opaque (about 1500) and partly a fresh borrowing of the Latin;^[5][7][8] the present spelling, rare before the 19th century, follows the French.^[5][3][9] The American Heritage Dictionary likewise takes the English word from both the Middle English opake and French opaque.^[10] The Latin adjective, which in post-classical Latin also meant obscure or mysterious, is of unknown origin.^{[5][6][3][11]} De Vaan rejects the old comparison with Sanskrit and Old Church Slavonic words for "turned away, behind", which would not give the Latin form, and mentions as a mere possibility a compound with the root of vacuus (“empty”) and vānus (“empty”);^[12] Merriam-Webster suggests a connection with ob (“towards, before”).^[13] Related forms are opaco, opaco and opaco.^[5]

Earliest recorded meaning

Lying in shade; dark, not lit: about 1440, in a Middle English translation of Palladius on farming, where fruit is to be hung up in place opake, in a dark place, glossed derke.^[5][2][6]

Semantic evolution

The literal Latin sense "shaded, dark" is now rare,^[5][7] and the modern meaning, "not letting light through, not transparent", is recorded from 1631,^[5] or from the 1640s in Etymonline.^[6] From 1646 it was also used of a surface that does not reflect or give out light, dull.^[5] Milton's Paradise Lost has body opaque, one of Johnson's quotations in 1755.^[14] The figurative sense "hard to understand, obscure" dates from 1761, in Sterne's Tristram Shandy,^[5][6] and for a time (about 1789–1886) the word also meant dull-witted, a sense still listed by Collins.^[5][15] In 1818 a London guide used opaque as slang for "drunk", contrasting it with a more transparent companion.^[16] Science extended it in 1860 to bodies that block other radiation, such as heat, sound or X-rays,^[5][15] and linguistics from 1949 to words whose meaning can no longer be read from their parts.^[5] The noun dates from 1742 (a place of darkness) and the verb, to make opaque, from 1718.^[5][13]

Timeline

• c. 1440 – opake, dark, shaded.^[5][2][3]
• 1631 – not letting light through, not transparent.^[5]
• 1646 – not reflecting light, dull.^[5]
• 1718 – verb, to make opaque.^[5][13]
• 1742 – noun, a region of darkness (obsolete by 1877).^[5][13]
• 1761 – hard to understand, obscure.^[5][6]
• 1860 – impervious to other radiation, such as heat or X-rays.^[5]
• 1949 – in linguistics, of a word whose meaning cannot be deduced from its parts.^[5]

Meanings

Adjective

1. Not letting light pass through; neither transparent nor translucent: opaque glass in the bathroom window.^[15][13][5]
2. Not letting other radiation, such as heat, sound or X-rays, pass through.^[15][5]
3. Hard to understand; obscure: The report was written in opaque legal language.^[15][5][10]
4. Not reflecting light; dull, without lustre.^[15][13][5]
5. (archaic) Dark, not lit; lying in shadow.^[13][5][7]

Noun

1. An opaque pigment or paint, used to block out parts of a photographic negative or print.^[13][15]

Verb

1. To make opaque, or to block out parts of a negative with opaque paint.^[13][5]

Word family

• opaquely
• opaqueness
• opacify
• semiopaque
• subopaque
• radiopaque

Related words

• opacity

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d 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 Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
4. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
5. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z 27 28 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
6. ^ a b c d e f Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
7. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
8. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
9. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
10. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
11. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
12. ^ de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
13. ^ a b c d e f g h i Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
14. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
15. ^ a b c d e f g Collins English Dictionary (2023), Glasgow: HarperCollins
16. ^ Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com