from
The Collaborative International Dictionary of English v.0.48
Horizon \Ho*ri"zon\, n. [F., fr. L. horizon, fr. Gr. ? (sc. ?)
the bounding line, horizon, fr. ? to bound, fr. ? boundary,
limit.]
1. The line which bounds that part of the earth's surface
visible to a spectator from a given point; the apparent
junction of the earth and sky.
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And when the morning sun shall raise his car
Above the border of this horizon. --Shak.
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All the horizon round
Invested with bright rays. --Milton.
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2. (Astron.)
(a) A plane passing through the eye of the spectator and
at right angles to the vertical at a given place; a
plane tangent to the earth's surface at that place;
called distinctively the sensible horizon.
(b) A plane parallel to the sensible horizon of a place,
and passing through the earth's center; -- called also
{rational horizon} or {celestial horizon}.
(c) (Naut.) The unbroken line separating sky and water, as
seen by an eye at a given elevation, no land being
visible.
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3. (Geol.) The epoch or time during which a deposit was made.
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The strata all over the earth, which were formed at
the same time, are said to belong to the same
geological horizon. --Le Conte.
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4. (Painting) The chief horizontal line in a picture of any
sort, which determines in the picture the height of the
eye of the spectator; in an extended landscape, the
representation of the natural horizon corresponds with
this line.
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5. The limit of a person's range of perception, capabilities,
or experience; as, children raised in the inner city have
limited horizons.
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6. [fig.] A boundary point or line, or a time point, beyond
which new knowledge or experiences may be found; as, more
powerful computers are just over the horizon.
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{Apparent horizon}. See under {Apparent}.
{Artificial horizon}, a level mirror, as the surface of
mercury in a shallow vessel, or a plane reflector adjusted
to the true level artificially; -- used chiefly with the
sextant for observing the double altitude of a celestial
body.
{Celestial horizon}. (Astron.) See def. 2, above.
{Dip of the horizon} (Astron.), the vertical angle between
the sensible horizon and a line to the visible horizon,
the latter always being below the former.
{Rational horizon}, and {Sensible horizon}. (Astron.) See
def. 2, above.
{Visible horizon}. See definitions 1 and 2, above.
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from
The Collaborative International Dictionary of English v.0.48
Apparent \Ap*par"ent\, a. [F. apparent, L. apparens, -entis, p.
pr. of apparere. See {Appear}.]
1. Capable of being seen, or easily seen; open to view;
visible to the eye; within sight or view.
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The moon . . . apparent queen. --Milton.
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2. Clear or manifest to the understanding; plain; evident;
obvious; known; palpable; indubitable.
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It is apparent foul play. --Shak.
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3. Appearing to the eye or mind (distinguished from, but not
necessarily opposed to, true or real); seeming; as the
apparent motion or diameter of the sun.
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To live on terms of civility, and even of apparent
friendship. --Macaulay.
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What Berkeley calls visible magnitude was by
astronomers called apparent magnitude. --Reid.
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{Apparent horizon}, the circle which in a level plain bounds
our view, and is formed by the apparent meeting of the
earth and heavens, as distinguished from the rational
horizon.
{Apparent time}. See {Time}.
{Heir apparent} (Law), one whose to an estate is indefeasible
if he survives the ancestor; -- in distinction from
presumptive heir. See {Presumptive}.
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Syn: Visible; distinct; plain; obvious; clear; certain;
evident; manifest; indubitable; notorious.
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