Age (noun)

1. The length of time that a person has lived or a thing has existed.
2. A particular stage in someone's life.
3. The latter part of life; old age.
4. A distinct period of history.
5. A long time.
6. A particular level of development or maturity reached at a certain time.

Origin:

Middle english: from old french aage, eage, from a ‘toward’ + a germanic base meaning ‘drive, impel’.

Examples:

1. He died at the age of 80.
2. She looks young for her age.
3. Old age can be difficult for many people.
4. The Bronze Age was a period of human history.
5. It took ages to finish the project.
6. He has reached an age where he is eligible to vote.
7. She is going through a difficult age right now.
8. The Stone Age is a period of prehistoric history.