- the line or circle that forms the apparent boundary between earth and sky.
- Astronomy.
- 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 ).
- 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 ).
- the limit or range of perception, knowledge, or the like.
- the scope of a person's interest, education, understanding, etc.: His horizons were narrow.
- a thin, distinctive stratum useful for stratigraphic correlation.
- any of the series of distinctive layers found in a vertical cross section of any well-developed soil.
- the apparent line that divides the earth and the sky
- astronomy
- the circular intersection with the celestial sphere of the plane tangential to the earth at the position of the observer
- 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
- the range or limit of scope, interest, knowledge, etc
- a thin layer of rock within a stratum that has a distinct composition, esp of fossils, by which the stratum may be dated
- a layer in a soil profile having particular characteristics
- likely or about to happen or appear
