"Old age" refers to people after the age of 50. In addition, "twilight" is only an approximate age, which means "old age". The so-called old age refers to the age when you don't take part in labor. According to the Book of Rites, fifty years later can be called twilight. In the twilight, the ancient word "Mo" is like the setting sun in the grass (the grass is full of prints), indicating that it will be late.

Extended data:

Old age comes from the following sources:

1, Four Kingdoms Cao Cao's Out of the Summer Gate: "Martyrs are more heroic in their twilight years."

2. Preface to Shen Yue in the Southern Dynasties: "Gao Han and Wu Song sang" Gale "in order to make it clear in the coming year, although they lacked chapters and sentences."

3. One of Du Fu's Odes to Monuments in the Tang Dynasty: "Yu Xin's life was the most bleak, and his poems stirred up rivers and mountains and passes in his twilight years." ?