horizon

noun

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

Examples of horizon in a Sentence

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

Ultimately, the best silver investment strategy will depend heavily on your goals, time horizon and comfort with risk, but in today's economic environment, silver in nearly any form is a compelling option. —Angelica Leicht, CBS News, 6 Mar. 2026

The artist, who was born in 1985 in Shanghai, has actively chosen an itinerant existence to reach beyond familiar horizons of both life and art, before eventually establishing a base in New York in late summer 2024. —Li Qi, Artforum, 6 Mar. 2026

New horizons call as the shimmering Sun in your curious 9th house trines buoyant Jupiter, filling you with inspiration to travel far and wide (literally or mentally). —Tarot.com, Sun Sentinel, 5 Mar. 2026

Whether in the cabin of a long-haul flight, on a research vessel in the middle of the Atlantic, or in a vehicle crossing a remote desert, travelers can expect a future of uninterrupted, gigabit-level internet that follows them across every horizon. —Mrigakshi Dixit, Interesting Engineering, 4 Mar. 2026

Word History

Etymology

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

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

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