remains vs physical object

remains and physical object both are nouns.

Word	Noun	Adjective	Verb	Adverb
remains	Yes	No	No	No
physical object	Yes	No	No	No

As nouns, physical object is a hypernym of remains; that is, physical object is a word with a broader meaning than remains:

remains: any object that is left unused or still extant
physical object: a tangible and visible entity; an entity that can cast a shadow

Other hypernyms of remains include object.

remains (noun)	physical object (noun)
the dead body of a human being	a tangible and visible entity; an entity that can cast a shadow
any object that is left unused or still extant
a relic that has been excavated from the soil