Source : Webster's Revised Unabridged Dictionary (1913)

Intestine \In*tes"tine\, n.; pl. {Intestines}. [L. intestinum:
   cf. F. intestin. See {Intestine}, a.]
   1. (Anat.) That part of the alimentary canal between the
      stomach and the anus. See Illust. of Digestive apparatus.

   2. pl. The bowels; entrails; viscera.

   {Large intestine} (Human Anat. & Med.), the lower portion of
      the bowel, terminating at the anus. It is adapted for the
      retention of fecal matter, being shorter, broader, and
      less convoluted than the small intestine; it consists of
      three parts, the c[ae]cum, colon, and rectum.

   {Small intestine} (Human Anat. & Med.), the upper portion of
      the bowel, in which the process of digestion is
      practically completed. It is narrow and contorted, and
      consists of three parts, the duodenum, jejunum, and ileum.

Source : WordNet®

small intestine
     n : the longest part of the alimentary canal; where digestion is
         completed