Russell's body vs inclusion

Russell's body and inclusion both are nouns.

Word	Noun	Adjective	Verb	Adverb
Russell's body	Yes	No	No	No
inclusion	Yes	No	No	No

As nouns, inclusion is a hypernym of Russell's body; that is, inclusion is a word with a broader meaning than Russell's body:

Russell's body: an inclusion body found in plasma cells in cases of cancer
inclusion: any small intracellular body found within another (characteristic of certain diseases)

Other hypernyms of Russell's body include cellular inclusion, inclusion body.

Russell's body (noun)	inclusion (noun)
an inclusion body found in plasma cells in cases of cancer	the act of including
	any small intracellular body found within another (characteristic of certain diseases)
	the relation of comprising something
	the state of being included