Source : Webster's Revised Unabridged Dictionary (1913)

Erythrosin \E*ryth"ro*sin\, n. [Gr. 'eryqro`s red.] (Chem.)
   (a) A red substance formed by the oxidation of tyrosin.
   (b) A red dyestuff obtained from fluoresce["i]n by the action
       of iodine.