plural of Metal Age

(see usage notes) The period of European history encompassing (roughly) 476–1000 CE. / (Ancient Greece) The Greek Dark Ages (c. 1100–750 BCE). / The dark ages of Cambodia (c. 1450–1863).

The period of European history, between the Early Middle Ages and the Late Middle Ages, that saw great social and political change.

The period of European history between the High Middle Ages and the Early Modern period

The period of the Middle Ages from about the fifth to the eleventh centuries that followed the collapse of the Western Roman Empire

Third-person singular simple present indicative form of age like milk

(statistics) The number of people in stated age ranges.

(education) An age at which a child is required to attend school.

(idiomatic, US, colloquial) A very long time.

How old one appears to be based solely on mental ability and function.