The difference between octogenarian and senile is that they refer to different ages. Where eighty to ninety years old means eighty to ninety years old, and senile means seventy to eighty years old.

The pronunciation of oldest and oldest is diémào, which is similar to the Chinese character "叠猫", and it comes from the Book of Jin - Li Chongzhuan, in which the original sentence reads, "I visited Chongzhou and Euphonium, and said that they are nearly oldest and oldest".

On the subject of old age, Cao Cao of the Three Kingdoms wrote in "The Wine" that "people are old and gray, and all of them are able to live to the end of their lives," meaning that people who live to be eighty or ninety years old are considered to be living to the end of their lives. Pu Songling's "Liaozhai Zhiyi" says: "You have no great honor, but it is enough to be aged eighty or ninety years". The two together mean high life expectancy, old age, and so on.

Appellation of age:

1, the total angle: refers to childhood. The language is from the Classic of Poetry, such as "Poetry - Wei Feng - rogue" "total angle of the feast", and "Qi Feng - Futian" "total angle Ruoxi". Later on, childhood was called "total horn". Tao Yuanming, in the preface to his poem "Rongmu", said, "The total angle of the road, the white head is not accomplished."

2. Tufts of hair: refers to childhood. In ancient times, when children were not crowned, their hair hung down, so "tufts of hair" was used to refer to childhood. In Pan Yue's "Ode to the Fields by Their Own Fathers" (藉亲颂田赋), the title of the article is "Being Brown with a Train, Tending Hair".

3. Hair Bundle: refers to teenagers. Generally, it refers to the age of about 15, when one should learn various skills. In the Da Dai Li Ji (Records of the Great Dai Rites), "When you have your hair tied up and attend the university, you will learn the great arts and fulfill the great rules."