The Horizon Is a Line That Marks a Limit
The horizon is where earth appears to meet sky. The Greek word means the bounding circle, and the figurative sense follows straight from it.
The horizon is the apparent line where the ground meets the sky. Greek *horizein* means to bound or to limit, so the horizon is literally the boundary of what can be seen from where you stand. When English says *broaden your horizons*, it is asking you to move.
- The line where earth meets sky. *A ship on the horizon.*
- The limit of experience or knowledge. *Broaden your horizons.*
- Time frame (business). *A five-year horizon.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | horizon | A clear horizon. |
| Plural | horizons | New horizons. |
| Adjective | horizontal | A horizontal line. |
| Adverb | horizontally | Laid horizontally. |
| Phrase | on the horizon | Change is on the horizon. |
How it is used in a sentence
- The sun dropped below the horizon.The literal line.
- Trouble is on the horizon.Meaning coming, but not yet here.
- Investors work to a longer horizon.Business and finance.
Horizon facts
- About five kilometres — the distance to the sea horizon for an adult standing on the shore
- Higher is further — from a hill or a plane the horizon retreats
- Event horizon — the boundary of a black hole, beyond which nothing returns
- Horizontal — parallel to the horizon
- Artificial horizon — the instrument that shows a pilot which way is level
From Greek *horizon kyklos*, the bounding circle, from *horizein*, to divide or limit, from *horos*, a boundary. Latin and Old French passed it on to English in the fourteenth century.
How far away is the horizon?
About five kilometres at sea for someone of average height at ground level. It increases with the square root of your height above the surface.
What is an event horizon?
The boundary around a black hole past which nothing, not even light, can escape. The name borrows the same idea of a limit to what can be seen.