York vs House of York

York and House of York both are nouns.

Word	Noun	Adjective	Verb	Adverb
York	Yes	No	No	No
House of York	Yes	No	No	No

As nouns, York and House of York are synonyms defined as:

York and House of York: the English royal house (a branch of the Plantagenet line) that reigned from 1461 to 1485; its emblem was a white rose

York (noun)	House of York (noun)
the English royal house (a branch of the Plantagenet line) that reigned from 1461 to 1485; its emblem was a white rose	the English royal house (a branch of the Plantagenet line) that reigned from 1461 to 1485; its emblem was a white rose