Ages

An age is the length of time that a person or thing has existed. The word is used in several related senses. Chronological age is the amount of time elapsed since a person was born, usually measured in years; biological age refers to an individual's physical condition, which may differ from their calendar age. Age is also an organizing concept in society, where groups are defined by commonly accepted age ranges and associated rights, responsibilities, and roles. Social policy and law often set minimum ages for activities such as driving, voting, drinking, and marriage; maximum ages for pensions or school attendance are also used in some systems.

In human development, ages are often described as stages: infancy, childhood, adolescence, adulthood, and old age. Developmental benchmarks vary across cultures, and life expectancy, health, and social expectations shape how these stages are experienced.

In archaeology and history, the term 'ages' is used to refer to broad cultural periods characterized by technologies and social organization, such as the Bronze Age and the Iron Age. In historical discourse, the term 'age' can also label major eras defined by distinctive features, such as the Information Age, the Renaissance, or the Space Age.

In geology and paleontology, an age is a subdivision of time within a larger unit such as an epoch or period, often defined by fossil assemblages or isotopic dating. Geologic ages span millions of years and are used to organize Earth's deep history.

Ages can be estimated or verified by dating methods, including radiometric dating, dendrochronology, and historical records, depending on the context and the timescale involved.