souvenir vs physical object

souvenir and physical object both are nouns.

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

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

souvenir: something of sentimental value
physical object: a tangible and visible entity; an entity that can cast a shadow

Other hypernyms of souvenir include object.

souvenir (noun)	physical object (noun)
something of sentimental value	a tangible and visible entity; an entity that can cast a shadow
a reminder of past events