The Collaborative International Dictionary of English v.0.48:

Drop \Drop\, v. t. [imp. & p. p. Droppedor Dropt; p. pr. &
   vb. n. Dropping.] [OE. droppen, AS. dropan, v. i. See
   Drop, n.]
   1. To pour or let fall in drops; to pour in small globules;
      to distill. "The trees drop balsam." --Creech.
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            The recording angel, as he wrote it down, dropped a
            tear upon the word and blotted it out forever.
                                                  --Sterne.
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   2. To cause to fall in one portion, or by one motion, like a
      drop; to let fall; as, to drop a line in fishing; to drop
      a courtesy.
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   3. To let go; to dismiss; to set aside; to have done with; to
      discontinue; to forsake; to give up; to omit.
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            They suddenly drop't the pursuit.     --S. Sharp.
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            That astonishing ease with which fine ladies drop
            you and pick you up again.            --Thackeray.
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            The connection had been dropped many years. -- Sir
                                                  W. Scott.
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            Dropping the too rough H in Hell and Heaven.
                                                  --Tennyson.
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   4. To bestow or communicate by a suggestion; to let fall in
      an indirect, cautious, or gentle manner; as, to drop hint,
      a word of counsel, etc.
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   5. To lower, as a curtain, or the muzzle of a gun, etc.
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   6. To send, as a letter; as, please drop me a line, a letter,
      word.
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   7. To give birth to; as, to drop a lamb.
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   8. To cover with drops; to variegate; to bedrop.
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            Show to the sun their waved coats dropped with gold.
                                                  --Milton.
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   To drop a vessel (Naut.), to leave it astern in a race or a
      chase; to outsail it.
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The Collaborative International Dictionary of English v.0.48:

Dropping \Drop"ping\, n.
   1. The action of causing to drop or of letting drop; falling.
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   2. pl. That which falls in drops; the excrement or dung of
      animals; -- often used in the plural.
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   Dropping bottle, an instrument used to supply small
      quantities of a fluid to a test tube or other vessel.

   Dropping fire, a continued irregular discharge of firearms.


   Dropping tube, a tube for ejecting any liquid in drops.
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WordNet (r) 3.0 (2006):

dropping
    adj 1: coming down freely under the influence of gravity; "the
           eerie whistle of dropping bombs"; "falling rain" [syn:
           dropping, falling]