haematemesis vs vomiting

haematemesis and vomiting both are nouns.

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

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

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

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

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