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.

Of or related to day-age creationism.

Early adolescence.

(Australia) Of the oldest age permitted to participate in a competition, and therefore ineligible to participate in its next season.

(Australia) Younger than the oldest age permitted to participate in a competition, and therefore eligible to participate in its next season.

(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.

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

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

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