extended family vs household

extended family and household both are nouns.

Word	Noun	Adjective	Verb	Adverb
extended family	Yes	No	No	No
household	Yes	No	No	No

As nouns, household is a hypernym of extended family; that is, household is a word with a broader meaning than extended family:

extended family: a family consisting of the nuclear family and their blood relatives
household: a social unit living together

Other hypernyms of extended family include family, home, house, menage.

extended family (noun)	household (noun)
a family consisting of the nuclear family and their blood relatives	a social unit living together