Dictionary / focus
focus
- noun
- verb
- from Latin
A point at which reflected or refracted rays of light converge.
1 All current definitions
Every sense of “focus” in current use, as recorded by Wiktionary. Older and obsolete senses are kept separately.
noun
- countableA 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.
- countableA point of a conic at which rays reflected from a curve or surface converge.
- uncountableThe fact of the convergence of light on the photographic medium.
Unfortunately, the license plate is out of focus in this image.
- uncountableThe 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.
- uncountableConcentration of attention.
I believe I can bring the high degree of focus required for this important job.
- countableSomething to which activity, attention or interest is primarily directed.
My studies are my main focus right now.
- countableThe 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.
- countableuncountableThe 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.
- countableuncountableThe most important word or phrase in a sentence or passage, or the one that imparts information.
- countableuncountableAn object used in casting a magic spell.
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.2004, Marian Singer, Trish MacGregor, The Only Wiccan Spell Book You'll Ever Need:
- countableuncountableThe centre of an older fish's scale, which is the point where a younger fish's scale starts to grow from.
verb
- transitiveTo cause (rays of light, etc) to converge at a single point.
- transitiveTo 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.
- intransitiveusuallyTo 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.
- transitiveTo direct attention, effort, or energy to a particular audience or task.
The president focused her remarks on the newcomers.
- intransitiveTo concentrate one’s attention.
If you're going to beat your competitors, you need to focus.
- intransitiveTo concentrate one's attention on something; to have as one's central point of interest, concern, etc.
I have to focus on my work.
- transitiveTo 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.
- To aggregate figures of accounts.
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.1897, Bram Stoker, Dracula, published 1993, page 67:
Cross-check: WordNet senses (12)
- nounthe concentration of attention or energy on something — also: focusing, focussing, focal point, direction, centering
- nounmaximum clarity or distinctness of an image rendered by an optical system
- nounmaximum clarity or distinctness of an idea
- nouna central point or locus of an infection in an organism — also: focal point, nidus
- nounspecial emphasis attached to something — also: stress
- nouna point of convergence of light (or other radiation) or a point from which it diverges — also: focal point
- nouna fixed reference point on the concave side of a conic section
- verbdirect one's attention on something — also: concentrate, center, centre, pore, rivet
- verbcause to converge on or toward a central point
- verbbring into focus or alignment; to converge or cause to converge; of ideas or emotions — also: concenter, concentre, focalize, focalise
- verbbecome focussed or come into focus — also: focalize, focalise
- verbput (an image) into focus — also: focalize, focalise, sharpen
Synonyms: adhere, align, anchor, apply, attend, base, center, centre, concentrate, direct, engage, fixate
Antonyms: defocus, dilute, ignore, muddy
2 History of the word
The etymology, the path the word travelled, and the words built from it.
The word’s journey, newest to oldest:
- English (today)focus
- Latinfocus “hearth, fireplace”
Borrowed from Latin focus (“hearth, fireplace”); see there for more. Related to 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."
Derivatives — words built from “focus”
Phrases & compounds
Related terms
Want to go deeper? See also “focus” on Etymonline ↗
3 Original language
Where “focus” came from before it was English.
4 Original meaning
What the word meant at the oldest point the record reaches.
Historical meaning — Webster’s 1913
A historical record, labelled as such: some of these senses are dated or have since shifted.
focus n. [L. focus hearth, fireplace; perh. akin to E. bake. Cf. Curfew, Fuel, Fusil the firearm.]
- A point in which the rays of light meet, after being reflected or refracted, and at which the image is formed; as, the focus of a lens or mirror.
- A point so related to a conic section and certain straight line called the directrix that the ratio of the distance between any point of the curve and the focus to the distance of the same point from the directrix is constant.
- A central point; a point of concentration.
focus v. t.
- To bring to a focus; to focalize; as, to focus a camera.
5 Use it with confidence
Model sentences from the sources, matched to the meaning they show. Read each one aloud, then make your own in the game.
nounMeaning: 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.
nounMeaning: The fact of the convergence of light on the photographic medium.
Unfortunately, the license plate is out of focus in this image.
nounMeaning: 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.
nounMeaning: Concentration of attention.
I believe I can bring the high degree of focus required for this important job.
nounMeaning: Something to which activity, attention or interest is primarily directed.
My studies are my main focus right now.
nounMeaning: 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.
nounMeaning: the concentration of attention or energy on something
the focus of activity shifted to molecular biology
nounMeaning: maximum clarity or distinctness of an image rendered by an optical system
in focus
out of focus
nounMeaning: maximum clarity or distinctness of an idea
the controversy brought clearly into focus an important difference of opinion
nounMeaning: a central point or locus of an infection in an organism
the focus of infection
Three steps to owning it
- Pick one meaning above and read its model sentence out loud.
- Say who or what the word is about in your own life, then build a sentence around that.
- Check it against the definition: would a careful reader understand exactly that meaning?
6 The mastery game
Play it here, or print it and do it with pen and paper. At the end you will know the meanings, history, origin and original meaning — and you will have used the word yourself.
Say it, then spell it
focus
/ˈfəʊ̯.kəs/ · fo·cus
Say the word out loud three times, slowly. Notice the stressed syllable. When you are ready, hide it and spell it from memory.
Activate Words · Word-mastery worksheet · Name: ______________________ Date: __________
focus
/ˈfəʊ̯.kəs/ · fo·cus · noun, verb
Step 1 — Say it and write it
Say “focus” out loud three times. Then cover the word and write it three times from memory.
Step 2 — Know every meaning
Read each definition. Then write it again in your own words.
Step 3 — Which meaning is it?
“The heat of sunlight at the focus of a magnifying glass can easily set dry leaves on fire.”
Circle the meaning used.
“Unfortunately, the license plate is out of focus in this image.”
Circle the meaning used.
“During this scene, the boy’s face shifts subtly from soft focus into sharp focus.”
Circle the meaning used.
Step 4 — History and origin
Write the word’s journey back in time (each language and form):
Write three words built from “focus” and what each means:
Step 5 — Original meaning
The earliest traceable form is Latin focus. What did it mean?
How does that original meaning connect to the meanings today?
Step 6 — Use it yourself
☐ I can explain its meanings ☐ I know its history ☐ I know its original language ☐ I know its original meaning ☐ I can use it confidently
Answer key — focus
Which meaning, sentence 1: B. A point at which reflected or refracted rays of light converge.
Which meaning, sentence 2: A. The fact of the convergence of light on the photographic medium.
Which meaning, sentence 3: C. The quality of the convergence of light on the photographic medium.
Origin: C. Latin (Latin focus)
Journey: English focus ← Latin focus
Some derivatives: apofocus, autofocus, bifocus, cofocus, disfocus, focus-group, focusless, hyperfocus
Original meaning: Latin focus — “hearth, fireplace”
Etymology: Borrowed from Latin focus (“hearth, fireplace”); see there for more. Related to fuel.
Sources: Wiktionary “focus” (https://en.wiktionary.org/wiki/focus#English), CC BY-SA 4.0, via kaikki.org; Princeton WordNet 3.0; Webster’s Revised Unabridged Dictionary (1913, public domain) via GCIDE. Worksheet from https://activatewords.com/w/focus