digester vs steriliser

digester and steriliser both are nouns.

Word	Noun	Adjective	Verb	Adverb
digester	Yes	No	No	No
steriliser	Yes	No	No	No

As nouns, steriliser is a hypernym of digester; that is, steriliser is a word with a broader meaning than digester:

digester: autoclave consisting of a vessel in which plant or animal materials are digested
steriliser: a device for heating substances above their boiling point; used to manufacture chemicals or to sterilize surgical instruments

Other hypernyms of digester include autoclave, sterilizer.

digester (noun)	steriliser (noun)
autoclave consisting of a vessel in which plant or animal materials are digested	a device for heating substances above their boiling point; used to manufacture chemicals or to sterilize surgical instruments