# lifetime

/ˈɫaɪfˌtaɪm/ (US) · /lˈaɪftaɪm/ (UK)

Source: https://englishreference.com/word/lifetime
Updated: 2026-06-19

## Senses

### 1. duration of life

noun · CEFR B1

the period of time during which someone is alive.

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

- He saw many incredible changes in technology during his lifetime.
- 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. functional period

noun · CEFR B2

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

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

- The battery has a lifetime of about three years before it needs replacing.
- 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. a very long time

noun · CEFR B2 · Informal

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

For teachers: a hyperbolic reference to an exceptionally long duration of time.

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

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

## Examples

- He spent his entire lifetime living in the same small village.
- Modern appliances are often designed with a shorter lifetime than those manufactured several decades ago.
- The philosopher argued that a single lifetime is insufficient to grasp the complexities of human nature, requiring instead the collective wisdom of many generations.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.