In geology|lang=en terms the difference between phanerozoic and proterozoic
is that
phanerozoic is (geology) a geologic eon from about 570 million years ago to the present, comprising the paleozoic, mesozoic and cenozoic eras while
proterozoic is (geology) of, or relating to the geologic eon from 2,500 ma to 5410±10 ma.
As adjectives the difference between phanerozoic and proterozoic
is that
phanerozoic is (geology) of, or relating to the phanerozoic eon while
proterozoic is (geology) of, or relating to the geologic eon from 2,500 ma to 5410±10 ma.
As proper nouns the difference between phanerozoic and proterozoic
is that
phanerozoic is (geology) a geologic eon from about 570 million years ago to the present, comprising the paleozoic, mesozoic and cenozoic eras while
proterozoic is (geology) the eon from 2,500 ma to 5410±10 ma, the beginning of the phanerozoic, marked by the build up of oxygen in the atmosphere and the emergence of primitive multicellular life.