Time represented by the time-stratigraphic unit called Stage (initial capital letter used in formal nomenclature): A series of rock strata formed in a single age on the geological timescale that signifies millions of years of deposition.

A certain stage of rock and the equivalent age of time have the same name and the same boundary.

Any time span in Earth history: Age can refer to the absolute existence of rocks or minerals, or the relative age of one rock unit compared with another.

The "age of reptiles" refers to the time when reptiles were dominant animals on the Earth.

Time before the present stated in years; referring to geologic events; actual age: Absolute age is generally based on measurement of radioactive decay rates and products of minerals or rock substances, such as the uranium lead method, carbon-14 method, etc.

Chronological date when one reaches legal adulthood: The age of majority isusually either 18 or 21; when juveniles are no longer under the jurisdiction of the juvenile courts, but rather the criminal courts.

The estimated age of an individual based on the person's structure: Anatomic age is the physical age of a human being and relates to the development or deterioration of the body as compared to that of other people of the same chronological age.

The age at which workers generally are no longer required to work for a living; especially, the age at which a pension is payable: The union contract for the agency stipulates an open retirement age for union members; in other words, there is no mandatory age for retirement.