opaco

Forms

opaco (feminine opaca, masculine plural opacos, feminine plural opacas)^[1]

Etymology

It is borrowed from Latin opācus (“shaded, shady, dark”).^[2][3][1] Nascentes calls it a learned word, which from “shady” came to mean “not transparent”.^[4] The Latin word lived on in popular words for the shady side of a valley, such as Catalan obac, Catalan ubac and Aragonese ubago, while Spanish opaco, like the Portuguese, is learned.^[5][6]

The Latin adjective, the opposite of aprīcus (“sunny”), is of unknown origin.^[1] It has long been compared with Sanskrit and Slavic words meaning “turned away, behind”, but de Vaan notes that these point to Proto-Indo-European *h₂epo-h₃kʷ-, which would not give the Latin form, and finds the proposed metathesis unlikely.^[7] He suggests, only as a possibility, *op-wākos (“situated towards the empty side”), with the root of vacuus (“empty”) and vānus (“empty, vain”).^[7][1]

Earliest recorded meaning

Cunha dates the word to the 16th century and Houaiss to 1635.^[3][2] Bluteau quotes João de Barros's third Década for the sense “dark, shadowy”: Que não sahia daquelle opaco, & sombrio lugar “who did not leave that dark and shadowy place”.^[8]

Semantic evolution

Bluteau gives both senses, “not transparent, impenetrable to light”, with examples from optics such as the opaque Moon reflecting the light of the Sun, and “very dark”, said of a place.^[8] Morais in 1789 has “not transparent” and “dark, shadowy”, as in bosque opaco.^[9] The modern dictionaries add “thick, dense” and the figurative “hard to understand, obscure”, and the DLP also has a sense in physics, blocking certain radiation, and one in linguistics.^[2][10][11] The noun opacidade is recorded in 1836.^[3]

Timeline

• 16th century – first record.^[3]
• 1635 – Houaiss's first date.^[2]
• 1712–1728 – Bluteau defines it and quotes João de Barros.^[8]
• 1789 – Morais gives “not transparent” and “dark, shadowy”.^[9]
• 1836 – first record of opacidade.^[3]

Meanings

Adjective

1. Not letting light through, not transparent: opaque.^[2][10][11]
2. Blocking certain radiation.^[10]
3. Without light; dark, shadowy: uma noite opaca.^[2][10][12]
4. Thick, dense, compact.^[2][10][11]
5. (figurative) Hard to understand; unclear, obscure.^[2][10][13]

Word family

• opacidade

Related words

• Latin opacus
• Catalan obac

References

1. ^ a b c d e f Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h Houaiss, Antônio; Villar, Mauro de Salles (2001), Dicionário Houaiss da língua portuguesa, Rio de Janeiro: Objetiva, p. s.v. opaco
3. ^ a b c d e Cunha, Antônio Geraldo da (2010), Dicionário etimológico da língua portuguesa, 4th ed., Rio de Janeiro: Lexikon, p. s.v. opaco
4. ^ Nascentes, Antenor (1966), Dicionário etimológico resumido, Rio de Janeiro: Instituto Nacional do Livro, p. s.v. opaco
5. ^ García de Diego, Vicente (1985), Diccionario etimológico español e hispánico, 2nd ed., Madrid: Espasa-Calpe (1st ed. 1954), p. s.v. opacus
6. ^ Meyer-Lübke, Wilhelm (1935), Romanisches etymologisches Wörterbuch, 3rd ed., Heidelberg: Winter
7. ^ a b de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
8. ^ a b c Bluteau, Raphael (1712–1728), Vocabulario portuguez e latino, 8 vols. + 2 supplement vols., Coimbra / Lisboa (CLP transcription, Universidade de Aveiro), p. s.v. opaco
9. ^ a b Silva, António de Morais (1789), Diccionario da lingua portugueza composto pelo padre D. Rafael Bluteau, reformado, e accrescentado, 2 vols., Lisboa: Simão Thaddeo Ferreira, p. 2, 134
10. ^ a b c d e f Academia das Ciências de Lisboa, Dicionário da Língua Portuguesa, revised online edition (2023–) of the Dicionário da Língua Portuguesa Contemporânea (2001), https://dicionario.acad-ciencias.pt, p. s.v. opaco
11. ^ a b c Ferreira, Aurélio Buarque de Holanda, Novo dicionário Aurélio da língua portuguesa, digital edition, p. s.v. opaco
12. ^ Dicionário Priberam da Língua Portuguesa, Lisboa: Priberam Informática, https://dicionario.priberam.org, p. s.v. opaco
13. ^ Aulete, Francisco Júlio Caldas, Dicionário contemporâneo da língua portuguesa (1st ed. 1881), online as Aulete Digital, Rio de Janeiro: Lexikon, https://aulete.com.br, p. s.v. opaco