1. The eon following the Hadean time and preceding the Phanerozoic eon; from about 3,800 million years ago until 544 million years ago
   - Precambrian, Precambrian aeon, Precambrian period

Type of: aeon, eon

• in the first place
• in the flesh
• in the lead
• in the least
• in the long run
• in the lurch
• in the main
• in the meantime
• in the midst
• in the nick of time
• in the public eye
• in the raw
• in the same breath
• in the south
• in the way
• in their right minds
• in theory
• in this
• in time
• in toto
• in touch
• in truth
• in turn
• in two ways
• in unison