nephrotomy vs incision

nephrotomy and incision both are nouns.

Word	Noun	Adjective	Verb	Adverb
nephrotomy	Yes	No	No	No
incision	Yes	No	No	No

As nouns, incision is a hypernym of nephrotomy; that is, incision is a word with a broader meaning than nephrotomy:

nephrotomy: incision into a kidney (usually to remove a kidney stone)
incision: the cutting of or into body tissues or organs (especially by a surgeon as part of an operation)

Other hypernyms of nephrotomy include section, surgical incision.

nephrotomy (noun)	incision (noun)
incision into a kidney (usually to remove a kidney stone)	the cutting of or into body tissues or organs (especially by a surgeon as part of an operation)
	a depression scratched or carved into a surface