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focus

Etymology and origin of the Latin word focus

History
Etymology tree
inherited borrowed derived
Latin focus
English curfew

Pronunciation

  • IPA (Classical): [ˈfɔ.kʊs][1]
  • IPA (Ecclesiastical): [ˈfɔː.kus][1]

Forms

focus m (genitive focī); second declension[1]

Etymology

The origin is uncertain.[2][3][1] A connection with fax (“torch”) is impossible in form, according to de Vaan, and an origin in a root of the shape *Dʰ-k(ʷ) would break the rules of PIE roots.[3] Hamp explained focus as a back-formation from foculus, which he derived from a root *dʰegʷʰ- (“to burn”); de Vaan finds this difficult in its chronology.[3][1] The word is also usually compared with Old Armenian բոց (bocʻ, “flame”).[1]

Ancient writers derived it from fovēre “to warm”: Varro said that anything that keeps a fire is a focus, and Ovid that the hearth is named from flames and because it warms all things.[4]

Earliest recorded meaning

It is found from Plautus on,[3][5] meaning the domestic hearth: in the Aulularia offerings are put on the hearth for the household god.[2]

Semantic evolution

The Roman focus was the hearth in the atrium, centre of the worship of the Lar of the household,[2] and so it stood for home and family, often in the pair arae et foci.[2] It was also the hearth of Vesta, a sacrificial hearth or altar, a funeral pyre, and the fire of a lighthouse or kiln.[2][4]

In Late Latin it came to mean fire itself,[1][6][7] the sense of its Romance descendants such as Italian fuoco, French feu and Spanish fuego.[1] In 1604 Kepler used it in mathematics for a point of convergence, perhaps from the burning point of a lens, and Hobbes brought it into English in the 1650s.[7]

Timeline

  • c. 250–184 BC – Plautus uses it for the hearth of the household god.[2][5]
  • 234–149 BC – Cato uses it for the hearth on which bread is baked.[2][5]
  • 81–43 BC – Cicero speaks of the public hearth of Vesta.[2][5]
  • 70–19 BC – Vergil uses it for funeral pyres.[2][5]
  • Early Middle Ages – It is used for fire.[6][7]
  • 1604 – Kepler uses it for a point of convergence.[7]
  • 1650s – Hobbes introduces it into English.[7]

Meanings

Noun

  1. A domestic hearth, fireplace, centre of the household cult.[2][4]
  2. (figurative) Home; a household, family.[2]
  3. A sacrificial hearth, an altar.[2][4]
  4. A brazier; a place where fires are lit, such as a kiln, lighthouse or funeral pyre.[2][4]
  5. (Late Latin) fire.[1][6]
  6. (Medieval Latin) A household, family.[6]

Descendants

  • Italian: fuoco[1]
  • Portuguese: fogo[1]
  • Romanian: foc[1]
  • Catalan: foc[1]
  • Occitan: fuòc, fòc, fuec, hoec, huec[1]
  • Galician: fogo[1]
  • Sardinian: fogu, focu[1]
  • Romansh: fieu, fiug[1]
  • Friulian: fûc[1]
  • Dalmatian: fuc[1]
  • Aromanian: foc, focu[1]
  • Old French: fu[1]
    • Middle French: feu[1]
  • Old Spanish: fuego[1]
    • Spanish: fuego[1]
  • English: focus (borrowed)[1]

Word family

  • focācius
  • focārius
  • foculus
  • focāceus
  • focācium
  • īnfocō
  • foculāre
  • English focus
  • English fuel

References

  1. ^ 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 Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l m Glare, P. G. W., ed. (2012), Oxford Latin Dictionary, 2nd ed., Oxford: Oxford University Press
  3. ^ a b c d de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
  4. ^ a b c d e Lewis, Charlton T.; Short, Charles (1879), A Latin Dictionary, Oxford: Clarendon Press
  5. ^ a b c d e Köbler, Gerhard (2010), Lateinisches Abkunfts- und Wirkungswörterbuch für Altertum und Mittelalter, online ed., koeblergerhard.de
  6. ^ a b c d Niermeyer, J. F. (1976), Mediae Latinitatis Lexicon Minus, Leiden: Brill
  7. ^ a b c d e Harper, Douglas, Online Etymology Dictionary, https://www.etymonline.com

Descendants

Cite this entry

“Focus.” Etymologically, 10 Oct. 2026, etymologically.com/la/focus. Accessed 10 Oct. 2026.

Last edited on .