fossil vs microfossil

fossil and microfossil both are nouns.

Word	Noun	Adjective	Verb	Adverb
fossil	Yes	Yes	No	No
microfossil	Yes	No	No	No

As nouns, microfossil is a hyponym of fossil; that is, microfossil is a word with a more specific, narrower meaning than fossil:

fossil: the remains (or an impression) of a plant or animal that existed in a past geological age and that has been excavated from the soil
microfossil: a fossil that must be studied microscopically

Other hyponyms of fossil include fucoid, belemnite, ammonite, ammonoid, guide fossil, index fossil, wormcast.

fossil (noun)	microfossil (noun)
the remains (or an impression) of a plant or animal that existed in a past geological age and that has been excavated from the soil	a fossil that must be studied microscopically
someone whose style is out of fashion

fossil (adjective)	microfossil (adjective)
characteristic of a fossil