'Lifetime' definitions:

Definition of 'lifetime'

noun

The period during which something is functional (as between birth and death); "the battery had a short life"; "he lived a long and happy life" [syn: life, lifetime, life- time, lifespan]

Definition of 'Lifetime'

From: GCIDE

Lifetime \Life"time`\ (l[imac]f"t[imac]m`), n. The time that life continues. [1913 Webster]

Synonyms of 'lifetime'

From: Moby Thesaurus

age,
animal spirits,
animate existence,
animation,
being alive,
birth,
existence,
for life,
generation,
having life,
immortality,
life,
lifelong,
liveliness,
livelong,
living,
long life,
longevity,
period of existence,
spriteliness,
viability,
vitality,
vivacity