# ketone

/ˈkitoʊn/ (US) · /kˈɛtəʊn/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/ketone
Updated: 2026-10-16

## Definition

a chemical your body makes when it burns fat for energy instead of sugar. The word also names a large group of similar chemicals used in science and industry.

For teachers: a class of organic compounds containing a carbonyl group bonded to two carbon atoms. Produced in the liver during fat metabolism and measured as markers of ketosis.

## Examples

- Your body makes ketones when you skip meals for a long time.
- After two days of fasting, the doctor checks his blood for ketones to see how his body uses fat.
- The lab identified elevated ketones in the sample, suggesting prolonged carbohydrate restriction had shifted metabolism toward fat oxidation.

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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.