Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

Proterozoic

play
adjective Pro·te·ro·zo·ic \ˌprä-tə-rə-ˈzō-ik, ˌprō-\

Definition of Proterozoic

  1. :  of, relating to, or being the eon of geologic time or the corresponding segment of rocks that includes the interval between the Archean and Phanerozoic eons, exceeds in length all of subsequent geologic time, and is marked by rocks that contain fossils indicating the first appearance of eukaryotic organisms (as algae) — see geologic time table

Proterozoic noun


Origin of proterozoic

Greek proteros former, earlier (from pro before) + International Scientific Vocabulary -zoic — more at for


First Known Use: 1899


Learn More about proterozoic


Seen and Heard

What made you want to look up Proterozoic? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

February 11, 2016

the holder of an office

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image33683556

How much does a batman (the Turkish unit of measurement) weigh?

100 pounds 196.5 pounds 16.96 pounds 2.2 pounds
Name That Thing

10 quick questions: hear them, spell them, and see how your skills compare to the crowd.

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ