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).
Also called rational 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.
Usually horizons. the scope of a person's interest, education, understanding, etc.: His horizons were narrow.
Geology. a thin, distinctive stratum useful for stratigraphic correlation.
Also called soil horizon. any of the series of distinctive layers found in a vertical cross section of any well-developed soil.
Origin of horizon
1540–50; < Latinhorizōn < Greekhorízōn (kýklos) bounding (circle), equivalent to horíz(ein) to bound, limit + -ōn present participle suffix (nominative singular); replacing Middle Englishorizonte < Middle French < Latinhorizontem, accusative of horizōn
Also called: visible horizon, apparent horizonthe apparent line that divides the earth and the sky
astronomy
Also called: sensible horizonthe circular intersection with the celestial sphere of the plane tangential to the earth at the position of the observer
Also called: celestial horizonthe 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
late 14c., orisoun, from Old French orizon (14c., Modern French horizon), earlier orizonte (13c.), from Latin horizontem (nominative horizon), from Greek horizon kyklos "bounding circle," from horizein "bound, limit, divide, separate," from horos "boundary." The h- was restored 17c. in imitation of Latin.
The apparent intersection of the Earth and sky as seen by an observer. Also called apparent horizon
See celestial horizon.
See sensible horizon.
Geology
A specific position in a stratigraphic column, such as the location of one or more fossils, that serves to identify the stratum with a particular period.
A specific layer of soil or subsoil in a vertical cross-section of land.
ArchaeologyA period during which the influence of a particular culture spread rapidly over a defined area.
