ironing vs household linen

ironing and household linen both are nouns.

Word	Noun	Adjective	Verb	Adverb
ironing	Yes	No	No	No
household linen	Yes	No	No	No

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

ironing: garments (clothes or linens) that are to be (or have been) ironed
household linen: drygoods for household use that are typically made of white cloth

Other hypernyms of ironing include garment, white goods.

ironing (noun)	household linen (noun)
the work of using heat to smooth washed clothes in order to remove any wrinkles	drygoods for household use that are typically made of white cloth
garments (clothes or linens) that are to be (or have been) ironed