The Collaborative International Dictionary of English v.0.48:

Saccharin \Sac"cha*rin\ (s[a^]k"k[.a]*r[i^]n), n. [F., from L.
   saccharon sugar.] (Chem.)
   A bitter white crystalline substance obtained from the
   saccharinates and regarded as the lactone of saccharinic
   acid; -- so called because formerly supposed to be isomeric
   with cane sugar (saccharose).
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Saccharine \Sac"cha*rine\ (? or ?), n. (Chem.)
   A trade name for benzoic sulphinide. [Written also
   saccharin.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

saccharin
    n 1: a crystalline substance 500 times sweeter than sugar; used
         as a calorie-free sweetener

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "saccharin":
   ambrosia, artificial sweetener, blackstrap, calcium cyclamate,
   cane syrup, clover honey, comb honey, corn syrup, cyclamates,
   edulcoration, honey, honeycomb, honeydew, honeypot, maple syrup,
   molasses, nectar, saccharification, sodium cyclamate, sorghum,
   sugar, sugar-making, sugaring off, sweetener, sweetening, sweets,
   syrup, treacle