Noun
the time of maturity when power and vigor are greatest
Source: WordNetIn poverty and other misfortunes of life, true friends are a sure refuge. The young they keep out of mischief; to the old they are a comfort and aid in their weakness, and those in the prime of life they incite to noble deeds. Aristotle
The Will-be and the Has-been touch us more nearly than the Is. So we are more tender towards children and old people than to those who are in the prime of life. Samuel Butler (novelist)
I don't consider 41 being in prime of life. Even if I conceived a child tomorrow I'd be 52 by the time it was 10. I'm not sure I'd have the energy, and I find that quite scary. Jeremy Northam
Many kings came to the throne at a young age and died in the prime of life, weakening royal power further. Source: Internet
Polybius also asserts that certain of the Celts fought naked, "The appearance of these naked warriors was a terrifying spectacle, for they were all men of splendid physique and in the prime of life." Source: Internet
Where Aristotle had set the prime of life at 37 years for men and 18 for women, the Visigothic Code of law in the 7th century placed the prime of life at twenty years for both men and women, after which both presumably married. Source: Internet