# focus
## English
### Etymology

Borrowed from Latin focus (“hearth, fireplace”); see there for more. Doublet of fuel.
Kepler introduced the term into mathematics and the sciences in describing elliptical orbits of planets (quote from Nicholas Mee) : "One of the interesting properties of an ellipse is that if there were a light bulb at one focus, then all the light that it emits would reflect off the ellipse and converge at the other focus. This is why Kepler originally used the name focus for these points."

### Pronunciation

* (UK) IPA: /ˈfəʊ.kəs/
** Audio (Southern England):(file)
* (US) IPA: /ˈfoʊ.kəs/
* Audio (US):(file)
* Hyphenation: fo‧cus
* Rhymes: -əʊkəs

### Noun

focus (countable and uncountable, plural foci or focuses or focusses)
* (countable, optics) A point at which reflected or refracted rays of light converge.
    Synonym: focal point
    The heat of sunlight at the focus of a magnifying glass can easily set dry leaves on fire.
* (countable, geometry) A point of a conic at which rays reflected from a curve or surface converge.
* (uncountable, photography, cinematography) The fact of the convergence of light on the photographic medium.
    Unfortunately, the license plate is out of focus in this image.
** 2013 July-August, Catherine Clabby, “Focus on Everything”, in American Scientist:Not long ago, it was difficult to produce photographs of tiny creatures with every part in focus. […] A photo processing technique called focus stacking has changed that. Developed as a tool to electronically combine the sharpest bits of multiple digital images, focus stacking is a boon to biologists seeking full focus on a micron scale.
* (uncountable, photography, cinematography) The quality of the convergence of light on the photographic medium.
    During this scene, the boy’s face shifts subtly from soft focus into sharp focus.
* (uncountable) Concentration of attention.
    I believe I can bring the high degree of focus required for this important job.
* (countable) Something to which activity, attention or interest is primarily directed.
    Synonym: focal point
    My studies are my main focus right now.
* (countable, seismology) The exact point of where an earthquake occurs, in three dimensions (underneath the epicentre).
    The earthquake's focus was at exactly 37 degrees north, 18 degrees south, seventy five meters below the ground.
* (graphical user interface) The status of being the currently active element in a user interface, often indicated by a visual highlight.
    Text entered at the keyboard or pasted from a clipboard is sent to the component which currently has the focus.
* (linguistics) The most important word or phrase in a sentence or passage, or the one that imparts information.
* An object used in casting a magic spell.
** 2004, Marian Singer, Trish MacGregor, The Only Wiccan Spell Book You'll Ever Need:Candles, in fact, are an essential ingredient in many spells. They can be used as either the focus of the spell or as a component that sets the spell's overall mood and tone.
* (ichthyology) The centre of an older fish's scale, which is the point where a younger fish's scale starts to grow from.
    Coordinate terms: annulus, circulus

#### Derived terms

* apofocus
* autofocus
* bifocus
* cofocus
* deep focus
* focus-group
* focus group
* focus hunting
* focus lamp
* focus lantern
* focusless
* focus puller
* hyperfocus
* in focus
* laser focus
* long-focus lens
* microfocus
* nanofocus
* out of focus
* overfocus
* perifocus
* prefocus
* pull-focus
* retrofocus
* self-focus
* soft focus
* underfocus
* virtual focus

#### Translations
### Verb

focus (third-person singular simple present focuses or focusses, present participle focusing or focussing, simple past and past participle focused or focussed)
* (transitive) To cause (rays of light, etc) to converge at a single point.
** 1961 February, “Talking of Trains: Collision at Newcastle”, in Trains Illustrated, pages 75–76:The difficulties of focussing colour-light signals on curved tracks to ensure maximum sighting distance were underlined in the recent official report [...] on a low-speed collision at Newcastle Central on July 25, 1960, between an unfitted freight and a diesel-hauled passenger train.
* (transitive, optics) To adjust (a lens, an optical instrument) in order to position an image with respect to the focal plane.
    You'll need to focus the microscope carefully in order to capture the full detail of this surface.
* (intransitive, optics, of a lens, optical instrument, etc.) To adjust itself or be adjusted such that light from a scene converges appropriately to create a clear image.
    I can't get the lens to focus.
    The camera focuses automatically on the subject's eyes.
* (transitive) To direct attention, effort, or energy to a particular audience or task.
    The president focused her remarks on the newcomers.
* (intransitive) To concentrate one’s attention.
    If you're going to beat your competitors, you need to focus.
* (intransitive, followed by on or upon) To concentrate one's attention on something; to have as one's central point of interest, concern, etc.
    I have to focus on my work.
* (computing, graphical user interface, transitive) To transfer the input focus to (a visual element), so that it receives subsequent input.
    The text box won't receive the user's keystrokes unless you explicitly focus it.
* (accounting, formerly) To aggregate figures of accounts.
** 1897, Bram Stoker, Dracula, published 1993, page 67:Whole pages of it are filled with masses of figures, generally single numbers added up in batches, and then the totals added in batches again, as though he were "focusing" some account, as the auditors put it.

#### Usage notes

The spellings with -ss- are more common in Commonwealth English than in American English, but in both varieties they are less common than the spellings focuses, focusing, focused.

#### Derived terms

* cryofocus
* defocus
* focusability
* focusable
* focuser
* focusser
* hydrofocus
* hyperfocus
* immunofocus
* microfocus
* misfocus
* overfocus
* prefocus
* refocus
* retrofocus
* unfocus

#### Related terms

* focal

#### Translations
### References

* ↑ Mee, Nicholas (2014) Gravity: Cracking the Cosmic Code, Virtual Image Publishing, →ISBN, page 74

### Anagrams

* Fusco

## Catalan
### Etymology

Borrowed from Latin focus. Compare the inherited doublet foc.

### Pronunciation

* IPA: (Central, Balearic, Valencia) [ˈfɔ.kus]
* Hyphenation: fo‧cus

### Noun

focus m (invariable)
* focus

## Dutch
### Etymology

Borrowed from New Latin focus. The figurative sense probably derives from English focus.

### Pronunciation

* IPA: /ˈfoː.kʏs/
* Audio:(file)
* Hyphenation: fo‧cus

### Noun

focus m (plural focussen)
* (optics, physics) focus
    Synonym: brandpunt
    Zij plaatste een convexe lens op de focus.She placed a convex lens on the focus.
* (figurative) focus, centre
    Die jodocus heeft geen focus.That clown doesn't have any focus.
* (linguistics) focus
    Focus is een belangrijk begrip in de informatiestructuur van zinnen.Focus is an important concept in the information structure of sentences.

#### Derived terms

* focaal
* focusafstand
* focussen

#### Related terms

* foyer

#### Descendants

* Afrikaans: fokus

### References

* ↑ Philippa, Marlies, Debrabandere, Frans, Quak, Arend, Schoonheim, Tanneke, van der Sijs, Nicoline (2003–2009) Etymologisch woordenboek van het Nederlands (in Dutch), Amsterdam: Amsterdam University Press

## Italian
### Etymology

Borrowed from Latin focus, whence also Italian fuoco (an inherited doublet).

### Pronunciation

* IPA: /ˈfɔ.kus/
* Rhymes: -ɔkus
* Hyphenation: fò‧cus

### Noun

focus m (invariable)
* focus (all senses)

### Anagrams

* Fusco

## Latin
### Etymology

* The origin is uncertain. Usually connected with Old Armenian բոց (bocʻ).
* Some connect this along with faciēs, facētus, fax to Proto-Indo-European *bʰeh₂- (“to shine”). In that case, cognate at the root level with Sanskrit भाति (bhā́ti), Ancient Greek φαίνω (phaínō, “to shine”), etc.
* Matasović, and Hamp before him, opt to derive this from Proto-Indo-European *dʰegʷʰ- (“to burn”); Matasović believes that the -c- would have spread from the nominative of a root noun *dʰṓgʷʰ-s (> *dʰṓkʷʰ-s).

### Pronunciation

* (Classical Latin) IPA: /ˈfo.kus/, [ˈfɔkʊs̠]
* (modern Italianate Ecclesiastical) IPA: /ˈfo.kus/, [ˈfɔːkus]

### Noun

focus m (genitive focī); second declension
* fireplace, hearth
* firepan, coal pan, brazier
* (figuratively) house, family
* (Late Latin) fire

#### Declension

Second-declension noun, with locative.
Locative used in the sense "by the hearth".

#### Synonyms

* (fire): ignis

#### Derived terms

* focāceus
* focācius
* focārius
* foculus
* īnfocō

#### Related terms

* focillare
* foculare

#### Descendants

* Balkan Romance:
** Aromanian: foc, focu
** Istro-Romanian: foc
** Megleno-Romanian: foc
** Romanian: foc
* Dalmatian:
** fuc
* Italo-Romance:
** Corsican: focu
** Italian: foco, fuoco
** Neapolitan: fuoco
** Sicilian: focu
* Insular Romance:
** Sardinian: fogu, focu
* North Italian:
** Gallo-Italic:
*** Emilian: fûg
*** Ligurian: fêugo
*** Lombard: fœg, fœi, fœv
*** Piedmontese: feu, feug
*** Romagnol: fug, fóg (Faenza, Imola)
** Friulian: fûc
** Istriot: fògo
** Ladin: fech, fesc
** Romansch: fieu, fiug
** Venetan: fogo
*** → Byzantine Greek: φουγκού (phounkoú)
**** → Turkish: fufu
***** → Greek: φουφού (foufoú)
* Gallo-Romance:
** Catalan: foc
** Franco-Provençal: fuè
** Old French: fu
*** Middle French: feu
**** French: feu
*** Walloon: feu
** Old Occitan: foc, fuec, fuoc
*** Occitan: fuòc, fòc, fuec, hoec (Gascony), huec (Gascony)
* Ibero-Romance:
** Aragonese: fuego
** Asturian: fueu, fuegu, ḥuego
** Extremaduran: hueu
** Mirandese: fuogo
** Old Galician-Portuguese: fogo
*** Fala: fogu
*** Galician: fogo
*** Portuguese: fogo (see there for further descendants)
** Old Spanish: fuego
*** Ladino: fuego
*** Spanish: fuego
Borrowings:
* → Catalan: focus
* → Dutch: focus
* → English: focus
* → Esperanto: fokuso
* → Finnish: fokus
* → French: focus
* → Galician: foco
* → German: Fokus
* → Italian: focus
* → Portuguese: foco
* → Russian: фо́кус (fókus)
* → Spanish: foco
* → Swedish: fokus

### References

* ↑ Matasović, Ranko (2010) “The etymology of Latin focus and the devoicing of final stops before *s in Proto-Indo-European”, in Historische Sprachforschung / Historical Linguistics‎, volume 123, Vandenhoeck & Ruprecht, →ISSN, →JSTOR, pages 212–216

### Further reading

* “focus”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
* “focus”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
* "focus", in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
* focus in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.
* Carl Meißner, Henry William Auden (1894) Latin Phrase-Book‎, London: Macmillan and Co. to fight for hearth and home: pro aris et focis pugnare, certare, dimicare
* “focus”, in Harry Thurston Peck, editor (1898), Harper's Dictionary of Classical Antiquities, New York: Harper & Brothers
* “focus”, in William Smith et al., editor (1890), A Dictionary of Greek and Roman Antiquities, London: William Wayte. G. E. Marindin
* De Vaan, Michiel (2008) Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill, →ISBN, pages 228-9

## Romanian
### Etymology

Borrowed from French focus or German Fokus.

### Noun

focus n (plural focusuri)
* focus