third age 
noun (the third age) British
The period in life of active retirement, following middle age.Many hope that the new age of retirement - the third age - will bring other opportunities and rewards - study, travel, volunteer work to name a few, not to mention health and access to the latest medical advances....
- It also turned out that the welfare state could not cope with the huge health costs in the third age - the age of physical decline.
- I've always maintained that, on moving into the third age, it's much better not to be a retired whatever and that, rather, one should aim to become something else, something new.
Derivatives
third ager
- And the prospect of young-at-heart ‘third agers’ viewing York as their playground is beguiling, if a little scary.
- A growing number of schools are responding to the academic needs of third agers by offering programs that enable nontraditional students to complete degrees amidst careers and other obligations.
- The typical third ager is also educated, with 86 percent having been to college.
- Follies
- follis
- follow
- followee
- follower
- followership
- following
- follow in someone's footsteps
- follow-my-leader
- follow on
- follow one's nose
- follow (or tread) in someone's footsteps
- follow (or tread) in someone's steps
- follow something through
- follow something up
- follow suit
- follow-the-leader
- follow through
- follow-up
- folly
- Folsom
- Fomalhaut
- foment
- fomentation
- fomenter