English Reference
noun

lifetime

n.
US /ˈɫaɪfˌtaɪm/ UK /lˈaɪftaɪm/ life·time UK spelling lifetime's, lifetime's

  1. 01 B1 Intermediate

    the period of time during which someone is alive.

    the duration of a person's life from birth to death.

    Simple

    He saw many incredible changes in technology during his lifetime.

    In context

    The scientist dedicated her entire lifetime to researching rare tropical plants in the hope of finding new medicinal compounds.

    Usage

    Often used with possessive adjectives like 'my lifetime' or 'her lifetime'.

  2. 02 B2 Upper Intermediate

    the length of time that a machine or product stays useful.

    the period during which a physical object or system remains functional or relevant.

    Simple

    The battery has a lifetime of about three years before it needs replacing.

    In context

    Engineers are working to extend the operational lifetime of the satellite to ensure it can continue transmitting data for another decade.

    Usage

    Commonly used in technical or consumer contexts regarding product durability.

  3. 03 B2 Upper Intermediate Informal

    a very long period of time, often used when you are waiting for something.

    a hyperbolic reference to an exceptionally long duration of time.

    Simple

    It felt like a lifetime before the doctor finally came out to speak to us.

    In context

    In the fast-moving world of digital fashion, six months can feel like a lifetime for a brand trying to stay relevant.

    Usage

    Usually appears in the singular with the indefinite article 'a'.

    Teacher's tip

    Remind students that this is an exaggeration; it doesn't literally mean a person's whole life.

In Sidmouth, families gathered to watch the event, with children describing it as a "once in a lifetime opportunity" and others comparing the shape of the Sun to a banana.

BBC News· 15 Aug 2026

While Fofana spent a lifetime waiting for the child she never held, Naju Ceesay, 58, spent hers remembering the children she lost.

Al Jazeera· 14 Aug 2026

From Middle English lyftyme, equivalent to life + time. Cognate with Icelandic líftími (“lifetime”). Compare also Saterland Frisian Lieuwendstied, Dutch leeftijd and levenstijd, German Low German Levenstied, German Lebenszeit, Danish livstid, Swedish livstid.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Middle English lyftyme
Level B2 · Upper Intermediate
Frequency Common
Updated