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

It was a soothing and relaxed space that suggested fun on the horizon.

From Los Angeles Times ● Jul. 28, 2026

The photographer was driving to his studio for a meeting when he realised the fire on the horizon was at the farm where it was based.

From BBC ● Jul. 26, 2026

This boundary is known as the particle horizon, the cosmological horizon, or the comoving horizon, depending on how stylish you feel in the moment.

From Science Daily ● Jul. 25, 2026

In the second week of the third month of the fourth year of his isolation, two British frigates finally appear on the horizon.

From The Wall Street Journal ● Jul. 23, 2026

A fiery orange glow spread above the horizon.

From "Fallout: Spies, Superbombs, and the Ultimate Cold War Showdown" by Steve Sheinkin

For moon watchers in Gloucestershire, Cleeve Hill, Painswick Beacon and May Hill are high ground locations offering wide horizons and clear vantage points.

From BBC ● Jul. 28, 2026

Black holes also present another challenge because they hide everything beyond their event horizons.

From Science Daily ● Jun. 14, 2026

Our research supports this conjecture, as we found that companies with more cheap stock experienced lower stock returns over longer horizons after going public.

From Salon ● Jun. 13, 2026

The stock market’s returns over shorter-term time horizons are largely statistical noise.

From MarketWatch ● Jun. 12, 2026

Best of all, the Levy family played chamber music every afternoon, thus broadening Shirley’s cultural horizons.

From "In the Year of the Boar and Jackie Robinson" by Bette Bao Lord

Related Words

• boundary
• perspective
• prospect
• scope