subtend

USAGE SUMMARY

The word "subtend" is correct and usable in written English.
It is a verb which means to extend beneath something or to form a boundary for something. Example sentence: The foundation stones subtended the garden wall.

✓ Grammatically correct

Encyclopedias

News & Media

Science

Human-verified examples from authoritative sources

Exact Expressions

13 human-written examples

The others are trillions of bacteria, each equally an individual, which are found in a person's gut, his mouth, his scalp, his skin and all of the crevices and orifices that subtend from his body's surface.A healthy adult human harbours some 100 trillion bacteria in his gut alone.

The Economist

Under scotopic conditions, the visual acuity may be only 0.04 so that lines would have to subtend about 25 minutes at the eye to be resolvable; this corresponds to a thickness of 4.4 centimetres (1.7 inches) at a distance of six metres (20 feet).

Encyclopedia Britannica

The testing of the eyes by the ophthalmologist or optometrist is essentially a determination of visual acuity; here the subject is presented with the Snellen chart, rows of letters whose details subtend progressively smaller angles at the eye.

Encyclopedia Britannica

Under reasonable light conditions, a normal eye with good visual acuity is capable of seeing two high-contrast points if they subtend a visual angle of at least one arc minute in size.

Encyclopedia Britannica

(A parsec is about 3.26 light-years and is the distance at which the radius of Earth's orbit would subtend an angle of one second).

Encyclopedia Britannica

The notation employed is somewhat obscure; a visual acuity of unity would be expressed as 6/6; an acuity of a half as 6/12, and so on; here the numerator is the viewing distance in metres from the chart and the denominator the distance at which details on the letters of the limiting row subtend one minute of arc at the eye.

Encyclopedia Britannica

Human-verified similar examples from authoritative sources

Similar Expressions

46 human-written examples

These subtended angles correspond to a viewing distance of roughly 2.2 times the screen width at the back row of the seating, down to 1.5 times the screen width at the front.

The Economist

Someone with 20/20 vision (6/6 in metric terms) can resolve a spatial pattern (of, say, a letter in the alphabet) where each element within it subtends an angle of one minute of arc when viewed from a distance of 20 feet (six metres).

The Economist

The ovulate cones are simpler, with each scale subtending a single ovule and two small scales.

Encyclopedia Britannica

Since the Sun's rays fall almost parallel on the Earth, the angle subtended by the arc l (representing the distance between Alexandria and Syene) at the centre of the Earth also equals α; thus the ratio of the Earth's circumference, C, to the distance, l, must equal the ratio of 360° to the angle α in symbols, C:l = 360°:α.

Encyclopedia Britannica

Observations with an interferometer (an instrument that measures the angle subtended by the diameter of a star at the observer's position), combined with parallax measurements (which yield a star's distance; see below Determining stellar distances), give sizes of 12 and 22 solar radii for Arcturus and Aldebaran A. Betelgeuse and Antares A are examples of supergiant stars.

Encyclopedia Britannica

Expert writing Tips

Best practice

When describing geometric relationships, particularly in technical writing or scientific reports, use "subtend" to precisely indicate that an angle corresponds to an arc on a circle.

Common error

While "subtend" can mean 'to extend beneath', reserve it for formal contexts like geometry and anatomy. Avoid using it as a synonym for simpler words like 'support' in everyday writing.

Linguistic Context

The primary grammatical function of "subtend" is as a verb, used to describe the relationship between an angle and an arc in geometry, or to indicate something extending beneath or opposite something else. Ludwig provides examples illustrating both usages.

Expression frequency: Uncommon

Frequent in

Encyclopedias

50%

News & Media

30%

Science

20%

Less common in

Ludwig's WRAP-UP

In summary, the word "subtend" functions as a verb, primarily in formal and scientific contexts to describe geometric relationships or spatial arrangements. As Ludwig AI confirms, its usage is grammatically correct, though not very frequent. The term commonly appears in encyclopedias and scientific literature, indicating a formal register. When clarity and precision are paramount, especially in technical descriptions, "subtend" provides a distinct advantage. However, remember to consider the audience and opt for more common synonyms if a simpler term would suffice.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

delimit

Emphasizes the aspect of setting boundaries or limits.

extend beneath

Focuses on the physical extent under something, similar to the 'underneath' aspect of "subtend".

stretch under

Emphasizes the act of extending physically beneath.

span

Emphasizes the act of stretching across or covering an area, comparable to enclosing an arc.

encompass

Highlights the covering or including aspect.

lie underneath

Highlights the position beneath something else.

underlie

Highlights the foundational aspect, suggesting something is at the base or support.

define

Focuses on the limiting and enclosing aspect, comparable to delimit.

be opposite to

Highlights a position facing directly across from something else.

form an angle at

Specifies the creation of an angle, relating to the geometric sense of "subtend".

FAQs

How is "subtend" used in geometry?

In geometry, "subtend" describes the relationship between an arc and an angle. For example, an angle is said to "subtend" an arc if its vertex lies on the circle's circumference and its sides pass through the endpoints of the arc.

What does "subtend" mean in a non-geometric context?

Outside of geometry, "subtend" can mean to extend or stretch underneath or opposite something. For example, "The crevices that "delimit" from the body's surface."

Is it appropriate to use "subtend" in general writing?

While grammatically correct, "subtend" is most appropriate in technical or scientific writing, particularly when discussing geometry or anatomy. Simpler words may be preferable in general writing.

What's the difference between "subtend" and "span"?

"Subtend" typically implies a specific geometric relationship between an angle and an arc, while "span" refers more broadly to extending across an area or range. You could say an angle "subtends" an arc, or that a bridge "spans" a river.