electrocautery vs thermocautery

electrocautery and thermocautery both are nouns.

Word	Noun	Adjective	Verb	Adverb
electrocautery	Yes	No	No	No
thermocautery	Yes	No	No	No

As nouns, thermocautery is a hypernym of electrocautery; that is, thermocautery is a word with a broader meaning than electrocautery:

electrocautery: application of a needle heated by an electric current to destroy tissue (as to remove warts)
thermocautery: cautery (destruction of tissue) by heat

electrocautery (noun)	thermocautery (noun)
application of a needle heated by an electric current to destroy tissue (as to remove warts)	cautery (destruction of tissue) by heat