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3 definitions found
 for Apparent horizon
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,
     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
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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.
     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.
     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
     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
     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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From WordNet (r) 3.0 (2006) :

  apparent horizon
      n 1: the line at which the sky and Earth appear to meet [syn:
           horizon, apparent horizon, visible horizon, sensible
           horizon, skyline]

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