unit vs natural object

unit and natural object both are nouns.

Word	Noun	Adjective	Verb	Adverb
unit	Yes	No	No	No
natural object	Yes	No	No	No

As nouns, natural object is a hyponym of unit; that is, natural object is a word with a more specific, narrower meaning than unit:

unit (noun)	natural object (noun)
an assemblage of parts that is regarded as a single entity	an object occurring naturally; not made by man
a single undivided whole
an organization regarded as part of a larger social group
a single undivided natural thing occurring in the composition of something else
any division of quantity accepted as a standard of measurement or exchange
an individual or group or structure or other entity regarded as a structural or functional constituent of a whole