Noun

• S: (n) geological time, geologic time (the time of the physical formation and development of the earth (especially prior to human history))
• direct hyponym / full hyponym
• S: (n) eon, aeon (the longest division of geological time)
• S: (n) period, geological period (a unit of geological time during which a system of rocks formed) "ganoid fishes swarmed during the earlier geological periods"
• direct hyponym / full hyponym
• part meronym
• has instance
• direct hypernym / inherited hypernym / sister term
• part holonym
• S: (n) era, geological era (a major division of geological time; an era is usually divided into two or more periods)
• part meronym
• has instance
• direct hypernym / inherited hypernym / sister term
• part holonym
• S: (n) epoch (a unit of geological time that is a subdivision of a period and is itself divided into ages)
• direct hypernym / inherited hypernym / sister term