Source : Webster's Revised Unabridged Dictionary (1913)

Hematemesis \Hem`a*tem"e*sis\, n. [NL., fr. Gr. a"i^ma,
   a"i`matos, blood + ? a vomiting, fr. ? to vomit.] (Med.)
   A vomiting of blood.

Source : WordNet®

hematemesis
     n : vomiting blood [syn: {haematemesis}]