life expectancy; average life span
Commonly used in demographic and health contexts to refer to the expected number of years a person will live from birth.
Japan's life expectancy is among the highest in the world.
As life expectancy increases, the pension system needs to be reviewed.
mean lifetime
Physics term for the average time a particle or system exists before decaying or changing state.
The mean lifetime of a muon is about 2.2 microseconds.
Life expectancy has increased due to advances in medicine.
My grandfather lived a long life, exceeding the average life expectancy.
The average life expectancy of Japanese people is about 84 years.