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.

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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

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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.

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horizon Idioms  

1. see on the horizon.

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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

All four planets will be above the horizon before sunrise, although some will be easier to spot than others.

From BBC ● Sep. 12, 2026

If he survives the rampaging zombies, there’s a major life change on the horizon: His girlfriend has recently told him she is pregnant, and he’s skeptical about the potential of fatherhood.

From The Wall Street Journal ● Sep. 9, 2026

On the horizon, you’ll see a Jabba the Hutt/Princess Leia statue.

From Los Angeles Times ● Sep. 8, 2026

From restructuring to the loan's role in Senegal's ongoing political drama, here is what is likely on the horizon.

From Barron's ● Sep. 3, 2026

On the eastern horizon, just above the distant blackness of the High Mountains, he found it: the starry shoulder of the Great Auroch.

From "Wolf Brother" by Michelle Paver

Meanwhile, he has advice for recent college graduates—a group including one of his own children: Broaden your horizons, whether geographically or otherwise.

From The Wall Street Journal ● Sep. 7, 2026

Regardless, should you ever feel that many people around you are looking increasingly smooth, there’s an easy solution that does not require Twilight Zone–style exile from society: Expand your social horizons a bit.

From Slate ● Sep. 2, 2026

Ever ambitious and eager to test new horizons, Keegan announced midway through the 1976-77 season that he would leave Liverpool at the end of the campaign.

From BBC ● Jul. 20, 2026

Inflation expectations for both one- and three-year horizons were up in a recent New York Fed survey.

From MarketWatch ● Jul. 10, 2026

As their horizons broadened, I would tell them about the people living in the Beje, people who never had a visitor, never a piece of mail.

From "The Hiding Place" by Corrie ten Boom

Related Words

• boundary
• perspective
• prospect
• scope