hematology vs haematology

hematology and haematology both are nouns.

Word	Noun	Adjective	Verb	Adverb
hematology	Yes	No	No	No
haematology	Yes	No	No	No

As nouns, hematology and haematology are synonyms defined as:

hematology and haematology: the branch of medicine that deals with diseases of the blood and blood-forming organs

hematology (noun)	haematology (noun)
the branch of medicine that deals with diseases of the blood and blood-forming organs	the branch of medicine that deals with diseases of the blood and blood-forming organs