period, period of time, time period - an amount of time; "a time period of 30 years"; "hastened the period of time of his recovery"; "Picasso's blue period"

Bronze Age - (archeology) a period between the Stone and Iron ages, characterized by the manufacture and use of bronze tools and weapons

Iron Age - (archeology) the period following the Bronze Age; characterized by rapid spread of iron tools and weapons

Stone Age - (archeology) the earliest known period of human culture, characterized by the use of stone implements

glacial epoch, glacial period, ice age - any period of time during which glaciers covered a large part of the earth's surface; "the most recent ice age was during the Pleistocene"