The Collaborative International Dictionary of English v.0.48:

Dextrin \Dex"trin\, n. [Cf. F. dextrine, G. dextrin. See
   Dexter.] (Chem.)
   A translucent, gummy, amorphous substance, nearly tasteless
   and odorless, used as a substitute for gum, for sizing, etc.,
   and obtained from starch by the action of heat, acids, or
   diastase. It is of somewhat variable composition, containing
   several carbohydrates which change easily to their respective
   varieties of sugar. It is so named from its rotating the
   plane of polarization to the right; -- called also British
   gum, Alsace gum, gommelin, leiocome, etc. See
   Achroodextrin, and Erythrodextrin.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dextrin
    n 1: any of various polysaccharides obtained by hydrolysis of
         starch; a tasteless and odorless gummy substance that is
         used as a thickening agent and in adhesives and in dietary
         supplements