[fan-er-uh-zoh-ik] 
Geology| 1. | the eon comprising the Paleozoic, Mesozoic, and Cenozoic eras. |
| 2. | of or pertaining to this eon. |
| Phan·e·ro·zo·ic (fān'ər-ə-zō'ĭk) adj. Of or relating to the geologic time period from approximately 570 million years ago to the present, comprising the Paleozoic, Mesozoic, and Cenozoic eras, and marked by an abundance of fossil evidence of life, especially higher forms, in the corresponding rocks. See Table at geologic time. n. The Phanerozoic Eon. [Greek phaneros, visible (from phainein, to cause to appear; see bhā-1 in Indo-European roots) + -zoic.] |
| Phanerozoic (fān'ər-ə-zō'ĭk) Pronunciation Key
The period of geologic time from about 540 million years ago to the present, including the Paleozoic, Mesozoic, and Cenozoic Eras. When this period of time was first defined, it was thought to coincide with the first appearance of life in the fossil record. It is now known that bacterial and other forms of life were present in the Precambrian Eon, and the Phanerozoic is understood to coincide with the appearance of life forms that evolved external skeletons. See Chart at geologic time. |
ər