metastatic tumor vs tumour

metastatic tumor and tumour both are nouns.

Word	Noun	Adjective	Verb	Adverb
metastatic tumor	Yes	No	No	No
tumour	Yes	No	No	No

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

metastatic tumor: a tumor that is malignant and tends to spread to other parts of the body
tumour: an abnormal new mass of tissue that serves no purpose

Other hypernyms of metastatic tumor include neoplasm, tumor, malignance, malignancy.

metastatic tumor (noun)	tumour (noun)
a tumor that is malignant and tends to spread to other parts of the body	an abnormal new mass of tissue that serves no purpose