hematemesis vs vomiting

hematemesis and vomiting both are nouns.

Word	Noun	Adjective	Verb	Adverb
hematemesis	Yes	No	No	No
vomiting	Yes	No	No	No

As nouns, vomiting is a hypernym of hematemesis; that is, vomiting is a word with a broader meaning than hematemesis:

hematemesis: vomiting blood
vomiting: the reflex act of ejecting the contents of the stomach through the mouth

Other hypernyms of hematemesis include disgorgement, emesis, puking, regurgitation, vomit.

hematemesis (noun)	vomiting (noun)
vomiting blood	the reflex act of ejecting the contents of the stomach through the mouth