(law) The age at which the rights and privileges of an adult are legally granted or recognized; i.e.; the age where a person ceases to be a minor legally and becomes a legal adult.

(mythology) The most recent and debased of the four or five classical Ages of Man; hence, any period characterized by wicked behavior. / An age characterized by the use of iron.

A restriction placed on an activity based on the age of the participants; either lower or higher limit.

(often capitalized) A modern spiritual and religious movement, covering a wide variety of alternative spiritual and philosophical ideas, that developed towards the end of the 20th century.

(often capitalized) Of or relating to the New Age movement. / Of or relating to New Age music.

(archaeology, paleontology) A broad prehistoric period during which humans widely used stone for toolmaking. / (figuratively, informal) Any extremely primitive or undeveloped era.

(archaeology) A period in a civilization's development when the most advanced metalworking has developed the techniques of smelting copper from natural outcroppings and alloys it to cast bronze.

Belonging in the Stone Age.

The age in which nuclear energy and nuclear weapons were developed.

the time of the Industrial Revolution