Umbilic

Umbilic \Um*bil"ic\, n. [From L. umbilicus: cf. F. ombilic. See
   {Navel}.]
   1. The navel; the center. [Obs.] "The umbilic of the world."
      --Sir T. Herbert.
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   2. (Geom.) An umbilicus. See {Umbilicus}, 5
      (b) .
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Umbilic \Um*bil"ic\, a. (Anat.)
   See {Umbilical}, 1.
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Umbilicus \Um`bi*li"cus\, n. [L. See {Umbilic}.]
   1. (Anat.) The depression, or mark, in the median line of the
      abdomen, which indicates the point where the umbilical
      cord separated from the fetus; the navel; the belly
      button, in humans.
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   2. (Gr. & Rom. Antiq.) An ornamented or painted ball or boss
      fastened at each end of the stick on which manuscripts
      were rolled. --Dr. W. Smith.
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   3. (Bot.) The hilum.
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   4. (Zool.)
      (a) A depression or opening in the center of the base of
          many spiral shells.
      (b) Either one of the two apertures in the calamus of a
          feather.
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   5. (Geom.)
      (a) One of the foci of an ellipse, or other curve. [Obs.]
      (b) A point of a surface at which the curvatures of the
          normal sections are all equal to each other. A sphere
          may be osculatory to the surface in every direction at
          an umbilicus. Called also {umbilic}.
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