[1] : The Collaborative International Dictionary of English v.0.48

tartar \tar"tar\, n. f. tartre cf. pr. tartari, sp., pg., 
   it. tartaro, ll. tartarum, lgr. ?; perhaps of arabic
   origin.
   1. chem. a reddish crust or sediment in wine casks,
      consisting essentially of crude cream of tartar, and used
      in marking pure cream of tartar, tartaric acid, potassium
      carbonate, black flux, etc., and, in dyeing, as a mordant
      for woolen goods; -- called also argol, wine stone,
      etc.
      1913 webster

   2. a correction which often incrusts the teeth, consisting of
      salivary mucus, animal matter, and phosphate of lime.
      1913 webster

   cream of tartar. chem. see under cream.

   tartar emetic med. chem., a double tartrate of potassium
      and basic antimony. it is a poisonous white crystalline
      substance having a sweetish metallic taste, and used in
      medicine as a sudorific and emetic.
      1913 webster
see also:
argol wine stone cream of tartar cream tartar emetic 

[2] : WordNet (r) 2.0

tartar emetic
     n : a poisonous colorless salt used as a mordant and in medicine
         syn: antimony potassium tartrate
see also:
antimony potassium tartrate 

Tartar >> T Words
Tartar, definition of term: Tartar
tartar_pag1.html

Emetic >> E Words
Emetic, definition of term: Emetic
emetic_pag1.html

Cream Of Tartar >> C Words
Cream Of Tartar, definition of term: Cream Of Tartar
cream+of+tartar_pag1.html