aging.

the length of time during which a being or thing has existed; length of life or existence to the time spoken of or referred to

trees of unknown age; His age is 20 years.

a period of human life, measured by years from birth, usually marked by a certain stage or degree of mental or physical development and involving legal responsibility and capacity

the age of discretion; the age of consent; The state raised the drinking age from 18 to 21 years.

the particular period of life at which a person becomes naturally or conventionally qualified or disqualified for anything

He was over age for military duty.

one of the periods or stages of human life

a person of middle age.

advanced years; old age

His eyes were dim with age.

a particular period of history, as distinguished from others; a historical epoch

the age of Pericles; the Stone Age; the age of electronic communications.

the period of history contemporary with the span of an individual's life

He was the most famous architect of the age.

a generation or a series of generations

ages yet unborn.

a great length of time

I haven't seen you for an age. He's been gone for ages.

the average life expectancy of an individual or of the individuals of a class or species

The age of a horse is from 25 to 30 years.

Psychology . the level of mental, emotional, or educational development of a person, esp. a child, as determined by various tests and based on a comparison of the individual's score with the average score for persons of the same chronological age.

Geology .

a period of the history of the earth distinguished by some special feature

the Ice Age.

a unit of geological time, shorter than an epoch, during which the rocks comprising a stage were formed.

any of the successive periods in human history divided, according to Hesiod, into the golden, silver, bronze, heroic, and iron ages.

Cards .

Poker . the first player at the dealer's left. Compare edge ( def. 10a ) .

eldest hand.

to grow old

He is aging rapidly.

to mature, as wine, cheese, or wood

a heavy port that ages slowly.

to make old; cause to grow or seem old

Fear aged him overnight.

to bring to maturity or a state fit for use

to age wine.

to store (a permanent magnet, a capacitor, or other similar device) so that its electrical or magnetic characteristics become constant. ?

of age

Law .

being any of several ages, usually 21 or 18, at which certain legal rights, as voting or marriage, are acquired.

being old enough for full legal rights and responsibilities.