The Collaborative International Dictionary of English v.0.48:

Pith \Pith\, n. [AS. pi?a; akin to D. pit pith, kernel, LG.
   peddik. Cf. Pit a kernel.]
   1. (Bot.) The soft spongy substance in the center of the
      stems of many plants and trees, especially those of the
      dicotyledonous or exogenous classes. It consists of
      cellular tissue.
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   2.
      (a) (Zool.) The spongy interior substance of a feather.
      (b) (Anat.) The spinal cord; the marrow.
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   3. Hence: The which contains the strength of life; the vital
      or essential part; concentrated force; vigor; strength;
      importance; as, the speech lacked pith.
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            Enterprises of great pith and moment. --Shak.
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   Pith paper. Same as Rice paper, under Rice.
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The Collaborative International Dictionary of English v.0.48:

Rice \Rice\, n. [F. riz (cf. Pr. ris, It. riso), L. oryza, Gr.
   ???, ???, probably from the Persian; cf. OPers. br[imac]zi,
   akin to Skr. vr[imac]hi; or perh. akin to E. rye. Cf. Rye.]
   (Bot.)
   A well-known cereal grass (Oryza sativa) and its seed. This
   plant is extensively cultivated in warm climates, and the
   grain forms a large portion of the food of the inhabitants.
   In America it grows chiefly on low, moist land, which can be
   overflowed.
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   Ant rice. (Bot.) See under Ant.

   French rice. (Bot.) See Amelcorn.

   Indian rice., a tall reedlike water grass (Zizania
      aquatica), bearing panicles of a long, slender grain,
      much used for food by North American Indians. It is common
      in shallow water in the Northern States. Called also
      water oat, Canadian wild rice, etc.

   Mountain rice, any species of an American genus
      (Oryzopsis) of grasses, somewhat resembling rice.

   Rice bunting. (Zool.) Same as Ricebird.

   Rice hen (Zool.), the Florida gallinule.

   Rice mouse (Zool.), a large dark-colored field mouse
      (Calomys palistris) of the Southern United States.

   Rice paper, a kind of thin, delicate paper, brought from
      China, -- used for painting upon, and for the manufacture
      of fancy articles. It is made by cutting the pith of a
      large herb (Fatsia papyrifera, related to the ginseng)
      into one roll or sheet, which is flattened out under
      pressure. Called also pith paper.

   Rice troupial (Zool.), the bobolink.

   Rice water, a drink for invalids made by boiling a small
      quantity of rice in water.

   Rice-water discharge (Med.), a liquid, resembling rice
      water in appearance, which is vomited, and discharged from
      the bowels, in cholera.

   Rice weevil (Zool.), a small beetle (Calandra oryzae, or
      Sitophilus oryzae) which destroys rice, wheat, and
      Indian corn by eating out the interior; -- called also
      black weevil.
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