When did the word immortality first come into being?

Ancient books, immortals, were first seen in the biographical records of Qin Shihuang. Before there were immortals, there were real people and human sages. During the Warring States Period, in the era of Zhuangzi, it was said that the sage was nameless, man was the highest realm that human beings could reach, and there was no immortal. Therefore, the immortal said that it was in the Warring States period after Zhuangzi and before Qin Shihuang's reunification. From the word "immortal", we can know that people are in the mountains, and it can be inferred that they went up to avoid war. The people of the Huang family cultivate their self-cultivation, hoping to transcend the secular and live forever. Slowly form a fairy.