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

Different investment horizons may seem manageable at closing, only to become a source of friction years later. — Anas Bhairi, Forbes.com, 6 Nov. 2026

As the Orion spacecraft traversed the far side of the moon, the Artemis II crew watched Earth disappear below the lunar horizon before losing radio contact with our planet. — Daisy Dobrijevic, Space.com, 5 Nov. 2026

When change doesn’t come as expected, the present moment has a way of billowing across an infinite horizon. — Sasha Geffen, Pitchfork, 3 Nov. 2026

The hunter’s three luminous studs stood out in a canopy awash with stars from horizon to horizon, the Milky Way a glittery paint stroke across the scene. — Heather Richardson, Condé Nast Traveler, 3 Nov. 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