Definitions for "Phanerozoic Eon"
The most recent eon, an interval of time from 542 Ma to the present.
A time period that consists of Precambrian, Paleozoic and Mesozoic Eras. This period began from the origin of the earth to approx. 65 m.y.a. This eon is the longest time period in the earth's geologic history (See : GEOLOGIC TIME)
the period from about 5,400 million years ago until the present