altering vs sterilisation

altering and sterilisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
altering	Yes	No	No	No
sterilisation	Yes	No	No	No

As nouns, sterilisation is a hypernym of altering; that is, sterilisation is a word with a broader meaning than altering:

altering: the sterilization of an animal
sterilisation: the act of making an organism barren or infertile (unable to reproduce)

Other hypernyms of altering include sterilization.

altering (noun)	sterilisation (noun)
the sterilization of an animal	the act of making an organism barren or infertile (unable to reproduce)
	the procedure of making some object free of live bacteria or other microorganisms (usually by heat or chemical means)