lifetime

noun

life·​time ˈlīf-ˌtīm 

1

a

: the duration of the existence of a living being (such as a person or an animal) or a thing (such as a star or a subatomic particle)

b

: life sense 12

2

: an amount accumulated or experienced in a lifetime

a lifetime of regrets

Synonyms of lifetime

• duration
• lifespan
• time
• life

Examples of lifetime in a Sentence

a lifetime spent traveling the world

It would have taken me a lifetime to read all those books.

Childhood seems a lifetime ago now!

a chemical with a lifetime of only a few minutes

the lifetime of a planet

Recent Examples on the Web

Rachel Carson’s contributions to our understanding of nature as both environmental home and habitat, whose balance must be protected and preserved, led her to a lifetime’s study of and writing about the oceans, coastlines, and lands of the United States. —Literary Hub, 8 June 2026

You’ll be rewarded with the raw, unbridled beauty that will stay with you for a lifetime. —Meghan Palmer, Condé Nast Traveler, 7 June 2026

For an average earner, that single set of choices is roughly a quarter-million dollars in lifetime income left on the table. —Jon Sabes, Fortune, 7 June 2026

Pic has surpassed Longlegs’ lifetime. —Anthony D'alessandro, Deadline, 7 June 2026

Word History

First Known Use

13th century, in the meaning defined at sense 1a

Phrases Containing lifetime

• of a lifetime
• once in a lifetime

Rhymes for lifetime

• aforetime
• allozyme
• anytime
• christmastime
• cybercrime
• dinnertime
• guggenheim
• isozyme
• lysozyme
• maritime
• mesenchyme
• overtime

Kids Definition

lifetime

noun

life·​time

ˈlīf-ˌtīm

1

: life entry 1 sense 3a

2

: life entry 1 sense 8