Webster’s Revised Unabridged Dictionary · 1913
Cystine
Cyst′ine (s?s′t?n; 104), n. [See Cyst.] (Physiol. Chem.) A white crystalline substance, C3H7NSO2, containing sulphur, occuring as a constituent of certain rare urinary calculi, and occasionally found as a sediment in urine.