The Collaborative International Dictionary of English v.0.48:

Food \Food\, n. [OE. fode, AS. f[=o]da; akin to Icel.
   f[ae][eth]a, f[ae][eth]i, Sw. f["o]da, Dan. & LG. f["o]de,
   OHG. fatunga, Gr. patei^sthai to eat, and perh. to Skr. p[=a]
   to protect, L. pascere to feed, pasture, pabulum food, E.
   pasture. [root]75. Cf. Feed, Fodder food, Foster to
   cherish.]
   1. What is fed upon; that which goes to support life by being
      received within, and assimilated by, the organism of an
      animal or a plant; nutriment; aliment; especially, what is
      eaten by animals for nourishment.
      [1913 Webster]

   Note: In a physiological sense, true aliment is to be
         distinguished as that portion of the food which is
         capable of being digested and absorbed into the blood,
         thus furnishing nourishment, in distinction from the
         indigestible matter which passes out through the
         alimentary canal as f[ae]ces.
         [1913 Webster]

   Note: Foods are divided into two main groups: nitrogenous, or
         proteid, foods, i.e., those which contain nitrogen, and
         nonnitrogenous, i.e., those which do not contain
         nitrogen. The latter group embraces the fats and
         carbohydrates, which collectively are sometimes termed
         heat producers or respiratory foods, since by oxidation
         in the body they especially subserve the production of
         heat. The proteids, on the other hand, are known as
         plastic foods or tissue formers, since no tissue can be
         formed without them. These latter terms, however, are
         misleading, since proteid foods may also give rise to
         heat both directly and indirectly, and the fats and
         carbohydrates are useful in other ways than in
         producing heat.
         [1913 Webster]

   2. Anything that instructs the intellect, excites the
      feelings, or molds habits of character; that which
      nourishes.
      [1913 Webster]

            This may prove food to my displeasure. --Shak.
      [1913 Webster]

            In this moment there is life and food
            For future years.                     --Wordsworth.
      [1913 Webster]

   Note: Food is often used adjectively or in self-explaining
         compounds, as in food fish or food-fish, food supply.
         [1913 Webster]

   Food vacuole (Zool.), one of the spaces in the interior of
      a protozoan in which food is contained, during digestion.


   Food yolk. (Biol.) See under Yolk.

   Syn: Aliment; sustenance; nutriment; feed; fare; victuals;
        provisions; meat.
        [1913 Webster]