The period of United States history from the end of the Civil War to the end of the 19th century, a time marked by rapid economic expansion, a lack of government regulation, and rampant corruption.

(UK) The age after retirement but while one is still young enough to be active; young old age.

The current era, characterised by the widespread and increasing use of digital technology in society.

Alternative form of age of extinction

The current period of Earth history characterised by large-scale extinction of lifeforms as a result of human activity.

(intransitive) To get older; to advance in age / (transitive) To cause to become older; to imagine to be older (especially of a fictional character)

Synonym of modern period or modern history (the period following postclassical history, in Europe known as the "Middle Ages", spanning from about 1500 to the present).

(US, slang, dated) A very long time.

(anthropology) An established social category or group consisting of people born during a certain time span who together move through a series of culturally defined age grades.

(anthropology) An organized, culturally defined social category of people with membership based on age; in some societies it is entered automatically when one reaches a certain age, while in others it is entered through an initiation rite and/or the payment of a fee.