horizon

American  

[huh-rahy-zuhn] / həˈraɪ zən /

noun

• horizons
  plural

1. 

   the line or circle that forms the apparent boundary between earth and sky.

2. Astronomy.

   1. the small circle of the celestial sphere whose plane is tangent to the earth at the position of a given observer, or the plane of such a circle sensible horizon.

   2. Also called rational horizon. the great circle of the celestial sphere whose plane passes through the center of the earth and is parallel to the sensible horizon of a given position, or the plane of such a circle celestial horizon.

3. the limit or range of perception, knowledge, or the like.

4. Usually horizons the scope of a person's interest, education, understanding, etc..

   His horizons were narrow.

   Synonyms:

   viewpoint, domain, perspective, world

5. Geology. a thin, distinctive stratum useful for stratigraphic correlation.

6. Also called soil horizon. any of the series of distinctive layers found in a vertical cross section of any well-developed soil.

---

horizon British  

/ həˈraɪzən /

noun

1. Also called: visible horizon, apparent horizon. the apparent line that divides the earth and the sky

2. astronomy

   1. Also called: sensible horizon. the circular intersection with the celestial sphere of the plane tangential to the earth at the position of the observer

   2. Also called: celestial horizon. the great circle on the celestial sphere, the plane of which passes through the centre of the earth and is parallel to the sensible horizon

3. the range or limit of scope, interest, knowledge, etc

4. a thin layer of rock within a stratum that has a distinct composition, esp of fossils, by which the stratum may be dated

5. a layer in a soil profile having particular characteristics See A horizon B horizon C horizon

6. likely or about to happen or appear

---

horizon Scientific  

/ hə-rī′zən /

1. 1. The apparent intersection of the Earth and sky as seen by an observer.

   2. See celestial horizon

   3. See sensible horizon

2. Geology

   1. A specific position in a stratigraphic column, such as the location of one or more fossils, that serves to identify the stratum with a particular period.

   2. A specific layer of soil or subsoil in a vertical cross-section of land.

3. Archaeology A period during which the influence of a particular culture spread rapidly over a defined area.

---

horizon Idioms  

1. see on the horizon.

---

Other Word Forms

Derived Forms

• horizonless
  adjective

Inflected Forms

Nouns

• horizons
  plural

---

Etymology

Origin of horizon

First recorded in 1540–50; from Latin horizōn, from Greek horízōn (kýklos) “bounding (circle),” equivalent to horíz(ein) “to bound, limit” + -ōn present participle suffix (nominative singular); replacing Middle English orizonte, from Middle French, from Latin horizontem, accusative of horizōn

---

Explanation

When you look out your window and note the furthest point you can see––the line where the sky meets the earth––that edge is called the horizon. Horizon can also mean the edge of something in a figurative sense. When you are thinking about your life, it can be difficult to get very far beyond where you are. Teenagers have a hard time imagining beyond the horizons of young adulthood. People expecting a baby often put much of their focus on infancy––having a child who can sit up or even walk is beyond the horizons of their thinking.

Example Sentences

See Examples For:

horizon horizons

Forty-five miles after it began, the journey through volcanoes, salt lakes, pine forests, aspens and a valley that stretches across the horizon comes to an end at a lonely intersection with U.S.

From Los Angeles Times ● Oct. 29, 2026

“Given the long time horizon of 25 years and the relatively low disbursement rate of 4%, the portfolio has the leeway to take on more risk,” he says.

From MarketWatch ● Oct. 29, 2026

Taken at 8:30 a.m. local Mars time, the scene reveals striking blue tones across the foreground while morning sunlight illuminates rugged cliffs known as yardangs along the horizon.

From Science Daily ● Oct. 22, 2026

Investors with a shorter investment horizon, however, should maintain a cautious stance on duration risk given still-elevated rate volatility, Cazzulani said.

From The Wall Street Journal ● Oct. 21, 2026

At the horizon, the color deepened to a thin rim of blue.

From "Caterpillar Summer" by Gillian McDunn

The MLA added that "opportunities that educate, inspire and broaden horizons are quietly lost while Stormont remains distracted from the issues that matter most to families".

From BBC ● Oct. 17, 2026

They typically invest in a mix of public and private assets and have long-term investment horizons.

From The Wall Street Journal ● Oct. 15, 2026

McQuarrie and Bernstein next expanded their horizon to look at trailing 17.5-year horizons, since that is how long it’s been since the March 2009 bottom that followed the global financial crisis.

From MarketWatch ● Oct. 12, 2026

It opened up my horizons to a lot of different forms of working out that I just didn’t know before.

From Los Angeles Times ● Sep. 14, 2026

When a human being is fed upon and consumed by one of them, especially in Africa, the event is telescoped against horizons of space and time, and takes on a feeling of immense antiquity.

From "The Hot Zone" by Richard Preston

Random Word

Spin the wheel and learn a new word!

---

Related Words

• boundary
• perspective
• prospect
• scope

---