focusとは

意味・読み方・使い方

発音

• (英国発音) IPA^(key): /ˈfəʊ.kəs/
  • (米国発音) IPA^(key): /ˈfoʊ.kəs/
  • 韻: -əʊkəs

名詞

focus (countable かつ uncountable, 複数形 foci または focuses または focusses)

1. (countable, optics) A point at which reflected or refracted rays of light converge.

   The heat of sunlight at the focus of a magnifying glass can easily set dry leaves on fire.

2. (countable, geometry) A point of a conic at which rays reflected from a curve or surface converge.
3. (uncountable, photography, cinematography) The fact of the convergence of light on the photographic medium.
   • 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.

   Unfortunately, the license plate is out of focus in this image.

4. (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.

5. (uncountable) Concentration of attention.

   I believe I can bring the high degree of focus required for this important job.

6. (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.

7. (graphical user interface) The indicator of the currently active element in a user interface.

   Text entered at the keyboard or pasted from a clipboard is sent to the component which currently has the focus.

8. (linguistics) The most important word or phrase in a sentence or passage, or the one that imparts information.
9. 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.

   • 2014, Kristen S. Walker, Witch Gate (page 180)

     I ran through what I knew about spells from Mom and other witchcraft sources, but nothing matched what I was used to seeing in her magic work. Usually she used herbs and other plants as a focus for the spell.

派生語

• focus hunting

動詞

focus (三人称単数 現在形 focuses または focusses, 現在分詞 focusing または focussing, 過去形および過去分詞形 focused または focussed)

1. (intransitive, followed by on または upon) To concentrate during a task.

   I have to focus on my work.

2. (transitive) To direct attention, effort, or energy to a particular audience or task.

   The president focused her remarks to the newcomers.

3. (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.

4. (transitive) 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.

5. (intransitive) To concentrate one’s attention.

   If you're going to beat your competitors, you need to focus.

6. (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.

使用する際の注意点

The spellings focusses, focussing, focussed are more common in Commonwealth English than in American English, but in both varieties they are less common than the spellings focuses, focusing, focused.

派生語

• focus group
• in focus
• out of focus
• soft focus

関連する語

• focal

アナグラム

• Fusco

Latin

語源

• The origin is uncertain. Usually connected with Old Armenian բոց (bocʿ).
• 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.
• In explaining how Kepler discovered the elliptical orbits, Nicholas Mee provides this explanation:

"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." (Gravity, 2014, p. 74)

発音

• (Classical) IPA^(key): /ˈfo.kus/, [ˈfɔ.kʊs̠]
• (Ecclesiastical) IPA^(key): /ˈfo.kus/, [ˈfɔː.kus]

名詞

focus m (genitive focī); second declension

1. fireplace, hearth
2. firepan, coal pan, brazier
3. (figuratively) house, family
4. (Vulgar Latin) fire

語形変化

Second-declension noun.

派生語

関連する語

• focillare
• foculare

同意語

• (fire): ignis

派生した語

参照

• 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, 1883–1887)
• focus in Gaffiot, Félix (1934) Dictionnaire Illustré Latin-Français, Hachette
• Carl Meissner; Henry William Auden (1894) Latin Phrase-Book‎^[1], London: Macmillan and Co.
  • to fight for hearth and home: pro aris et focis pugnare, certare, dimicare