Young man. The dividing line between the elderly was called in ancient times, what?

The dividing line between youth and maturity is thirty years old.

The dividing line between prime of life and middle age is forty years old.

The dividing line between know life and middle-aged and elderly people who know tomorrow is fifty years old.

The age of ancient people is sometimes not expressed by numbers, not by telling someone's age or age directly, but by an age-related title instead. Stripes are children aged three or four to eight or nine (stripes, short hair hanging down from the heads of ancient children). The total angle is a teenager between the ages of eight or nine and thirteen or fourteen (ancient children divided their hair into left and right halves and tied it in a knot at the top of their heads, which is shaped like two horns, so it is called "total angle"). Cardamom is thirteen or fourteen years old to fifteen or sixteen years old (Cardamom is a plant that blooms in early summer, but not yet in midsummer, which means that people are still underage, so it is called "cardamom youth"). Hair was tied when a man was fifteen (when he was fifteen, a man would dissolve the original corner and tie it into a bundle). The weak crown is a man of twenty years old (the ancient man was crowned at the age of twenty, indicating that he had reached adulthood, so he was called "weak crown" because he had not yet reached the prime of life). Li is a thirty-year-old man. Not confused is that the man is forty (not confused, "not confused, not confused"). Know life is a 50-year-old man (know life, meaning "knowing destiny"). This flower is sixty years old. Gu Xi is seventy years old. Mao and die mean eighty or ninety years old. Period refers to one hundred years old.