pheochromocytoma vs tumour

pheochromocytoma and tumour both are nouns.

Word	Noun	Adjective	Verb	Adverb
pheochromocytoma	Yes	No	No	No
tumour	Yes	No	No	No

As nouns, tumour is a hypernym of pheochromocytoma; that is, tumour is a word with a broader meaning than pheochromocytoma:

pheochromocytoma: a vascular tumor of the adrenal gland; hypersecretion of epinephrine results in intermittent or sustained hypertension
tumour: an abnormal new mass of tissue that serves no purpose

Other hypernyms of pheochromocytoma include neoplasm, tumor.

pheochromocytoma (noun)	tumour (noun)
a vascular tumor of the adrenal gland; hypersecretion of epinephrine results in intermittent or sustained hypertension	an abnormal new mass of tissue that serves no purpose