The Collaborative International Dictionary of English v.0.48:

Bread \Bread\ (br[e^]d), n. [AS. bre['a]d; akin to OFries.
   br[=a]d, OS. br[=o]d, D. brood, G. brod, brot, Icel.
   brau[eth], Sw. & Dan. br["o]d. The root is probably that of
   E. brew. [root]93. See Brew.]
   1. An article of food made from flour or meal by moistening,
      kneading, and baking.
      [1913 Webster]

   Note:

   Raised bread is made with yeast, salt, and sometimes a
      little butter or lard, and is mixed with warm milk or
      water to form the dough, which, after kneading, is given
      time to rise before baking.

   Cream of tartar bread is raised by the action of an
      alkaline carbonate or bicarbonate (as saleratus or
      ammonium bicarbonate) and cream of tartar (acid tartrate
      of potassium) or some acid.

   Unleavened bread is usually mixed with water and salt only.
      [1913 Webster]

   A["e]rated bread. See under A["e]rated.

   Bread and butter (fig.), means of living.

   Brown bread, Indian bread, Graham bread, Rye and
   Indian bread. See Brown bread, under Brown.

   Bread tree. See Breadfruit.
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   2. Food; sustenance; support of life, in general.
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            Give us this day our daily bread.     --Matt. vi. 11
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WordNet (r) 3.0 (2006):

bread and butter
    n 1: the financial means whereby one lives; "each child was
         expected to pay for their keep"; "he applied to the state
         for support"; "he could no longer earn his own livelihood"
         [syn: support, keep, livelihood, living, bread and
         butter, sustenance]