永生 literally means 'eternal life'—combining 永 (yǒng), meaning 'forever' or 'perpetual,' and 生 (shēng), meaning 'life' or 'to live.' Together, they express the philosophical or religious concept of immortality: life that never ends. The term carries strong connotations of transcendence, divinity, or scientific ambition—often appearing in Daoist texts, modern sci-fi, medical ethics debates, or discussions about aging and longevity research.

In everyday usage, 永生 is not used casually like 'long life' (长寿). It’s formal, literary, or abstract—common in academic writing, literature, film titles, or philosophical discourse. While it can describe biological immortality, it more frequently implies spiritual continuity (e.g., in Buddhist or Daoist thought) or symbolic endurance (e.g., 'eternal life' of a cultural legacy). It is rarely used to describe actual human lifespans, since Chinese culture traditionally emphasizes harmony with natural cycles rather than literal endless existence.