Source : Webster's Revised Unabridged Dictionary (1913)

Guanidine \Gua"ni*dine\, n. (Physiol. Chem.)
   A strongly alkaline base, {CN3H5}, formed by the oxidation of
   guanin, and also obtained combined with methyl in the
   decomposition of creatin. Boiled with dilute sulphuric acid,
   it yields urea and ammonia.