horizon
Pluralhorizons
- 1The visible line in the distance where the sky appears to meet the earth or sea.
A thin band of orange light spread along the horizon at dawn.
From the summit, the curve of the horizon stretched in every direction.
Similarskyline
Note
The literal line the other senses grow from, and its history explains them. Middle English orisonte came through French and Latin from Greek horízōn, built on hóros, "boundary." The horizon is the edge that bounds what the eye can reach, which is why we speak of the whole sweep of it. Skyline and skysill name the same edge, and the figurative "limit of experience" moves that boundary from the eye to the mind.
- 2The outer bounds of a person's knowledge, experience, or interests, or more generally any boundary or threshold.
Studying philosophy pushed the horizon of his thinking far beyond what he expected.
Travel has a way of broadening one's horizons.
Similarscope, range, outlook, perspective, limit
Note
Two fixed phrases carry most of this figurative sense. Broaden or open your horizons takes the plural and means widening what you know: F. A. Hayek writes of a philosophy that "opens new horizons" (1949). On the horizon takes the singular and means approaching or in prospect, as in a new treatment on the horizon. Eduardo Galeano's conquerors who "appeared on the horizon" (1997) sit on the border between figure and fact.
- 3The boundary or extent of any dimension within which a person exists.
Mortality forms the ultimate horizon of every human life.
Within the horizons of a single lifetime, only so much can ever be accomplished.
Similarlimit, boundary, bound, confines
Note
A philosopher's horizon is the outer bound of a dimension that frames a life, such as mortality. Miguel de Beistegui's Thinking with Heidegger (2003) calls mortality "that very horizon" which Heidegger revealed in Being and Time as "the unsurpassable and defining possibility." Unlike the limit of experience, which travel or study can broaden, this horizon is not pushed back. It defines the existence it encloses.
- 4A level line or surface of any kind.
Far from any coastline, the navigator poured mercury into a shallow tray to give his sextant a true horizon.
He aligned the new shelf to the horizon marked by his spirit level.
Similarlevel, horizontal, plane
- 5A distinct layer of soil or rock within a vertical sequence.
Like the bands of color in a sandstone cliff, each one laid down at a different time.
Geologists labeled each horizon by its color and texture.
The upper horizon held far more organic matter than the layers beneath it.
Similarlayer, stratum, bed, level
Note
Soil science applies the level-line idea to something underground. Each horizon is a layer lying roughly parallel to the surface. It is set apart from the layers above and below by physical or chemical properties it acquired as the soil formed. The word sits close to stratum, but in a soil profile it names layers made by soil formation itself. The plural here counts layers, not the figurative horizons one broadens.
- 6A cultural sub-period or level situated within a larger span of time.
Like a brief musical fad that briefly ties a whole generation together.
The excavation revealed artifacts from a distinct cultural horizon.
Researchers dated the horizon to roughly the twelfth century.
Similarphase, period, level, stage, stratum
Note
Archaeologists use the word for a slice of time rather than of earth. A horizon is a widely distributed set of cultural traits taken to have spread quickly, marking a fairly brief sub-period within a longer regional sequence. The usage is chiefly American. On a dig where both meanings are in play, keep it distinct from the soil layer: one horizon is dated, the other is dug through.
- 7The point at which a chess-playing program stops searching for further moves.
The chess engine evaluated every line up to its horizon, then stopped.
Extending the horizon by two plies sharpened the program's tactical vision.
Note
Game-tree search gives the word a hard edge: the depth limit past which a chess engine stops evaluating moves. Its best-known consequence is the horizon effect. When a damaging consequence lies just beyond that limit, the program cannot see it and plays as though it were not there. The image is borrowed straight from the literal horizon, since whatever lies past the line is invisible.
Practice
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Origin
This word came into Middle English through Middle and Old French, ultimately from Latin 'horizōn' and Ancient Greek 'horízōn', which derives from 'hóros' meaning 'boundary'.