horizon

1 of 2

noun (1)

ho·​ri·​zon hə-ˈrī-zᵊn 

1

a

: the line where the earth seems to meet the sky : the apparent junction of earth and sky

sailing toward the horizon

b

: the great circle on the celestial sphere formed by the intersection of the celestial sphere with a plane tangent to the earth's surface at an observer's position see azimuth illustration

c

: range of perception or experience

broaden your horizons

d

: something that might be attained

opening up new horizons in the field of cancer research

2

a

geology : a natural soil layer deposited at a particular time usually identified by distinctive fossils

b

geology : any of the reasonably distinct layers of soil or its underlying material in a vertical section of land

c

anthropology : a cultural area or level of development indicated by separated groups of artifacts

horizonal

hə-ˈrī-zᵊn-əl 

adjective

horizon blue

2 of 2

noun (2)

1

: a variable color averaging a light greenish blue to blue

2

or less commonly horizon : a greenish white

Examples of horizon in a Sentence

Noun (1)

We sailed toward the horizon.

The sun rose slowly over the eastern horizon.

These discoveries have opened up new horizons in the field of cancer research.

Recent Examples on the Web

Noun

Documentation from the International Atomic Energy Agency (IAEA) indicates that these fuel cycles could support global electrical infrastructure requirements over a long time horizon. —Aman Tripathi, Interesting Engineering, 10 June 2026

Because of the long-term horizon, experts say immediate economic and demographic fallout would be limited. —Jamey Keaten, Fortune, 10 June 2026

Hey, this is a brief dark cloud on your horizon. —Georgia Nicols, Denver Post, 10 June 2026

Though the road to reach that horizon still looks long, the R2 deserves to bring Rivian to the masses and ever closer to bringing that vision for the future to fruition. —ArsTechnica, 9 June 2026

Word History

Etymology

Noun (1)

Middle English orizon, from Late Latin horizont-, horizon, from Greek horizont-, horizōn, from present participle of horizein to bound, define, from horos boundary; perhaps akin to Latin urvum curved part of a plow

First Known Use

Noun (1)

14th century, in the meaning defined at sense 1a

Phrases Containing horizon

• A horizon
• artificial horizon
• B horizon
• C horizon
• cloud on the horizon
• event horizon
• gyro horizon
• on the horizon
• the horizon

Rhymes for horizon

• mizen
• spiegeleisen

Kids Definition

horizon

noun

ho·​ri·​zon ˈhə-ˈrīz-ᵊn 

1

: the line where the earth or sea seems to meet the sky

2

: the limit or range of a person's outlook or experience

reading broadens our horizons

3

: a distinct layer of soil or its underlying material in a vertical section of land

horizonal

-ˈrīz-nəl 

-ᵊn-əl

adjective