Source : Webster's Revised Unabridged Dictionary (1913)

Archaeozoic \Ar`ch[ae]*o*zo"ic\, a. [Gr. 'archai^os ancient +
   zw^,on animal.] (Zo["o]l.)
   Like or belonging to the earliest forms of animal life.

Source : WordNet®

Archaeozoic
     n : the time from 3,800 million years to 2,500 million years
         ago; earth's crust formed; unicellular organisms are
         earliest forms of life [syn: {Archean}, {Archean eon}, {Archean
         aeon}, {Archeozoic}, {Archeozoic eon}, {Archaeozoic aeon}]