The Collaborative International Dictionary of English v.0.48:

Departure \De*par"ture\ (?; 135), n. [From Depart.]
   1. Division; separation; putting away. [Obs.]
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            No other remedy . . . but absolute departure.
                                                  --Milton.
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   2. Separation or removal from a place; the act or process of
      departing or going away.
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            Departure from this happy place.      --Milton.
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   3. Removal from the present life; death; decease.
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            The time of my departure is at hand.  --2 Tim. iv.
                                                  6.
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            His timely departure . . . barred him from the
            knowledge of his son's miseries.      --Sir P.
                                                  Sidney.
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   4. Deviation or abandonment, as from or of a rule or course
      of action, a plan, or a purpose.
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            Any departure from a national standard. --Prescott.
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   5. (Law) The desertion by a party to any pleading of the
      ground taken by him in his last antecedent pleading, and
      the adoption of another. --Bouvier.
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   6. (Nav. & Surv.) The distance due east or west which a
      person or ship passes over in going along an oblique line.
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   Note: Since the meridians sensibly converge, the departure in
         navigation is not measured from the beginning nor from
         the end of the ship's course, but is regarded as the
         total easting or westing made by the ship or person as
         he travels over the course.
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   To take a departure (Nav. & Surv.), to ascertain, usually
      by taking bearings from a landmark, the position of a
      vessel at the beginning of a voyage as a point from which
      to begin her dead reckoning; as, the ship took her
      departure from Sandy Hook.

   Syn: Death; demise; release. See Death.
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