# dehydration

/ˌdihaɪˈdɹeɪʃən/ (US) · /dˌiːhaɪdɹˈeɪʃən/ (UK) · CEFR B2 · Noun

Source: https://englishreference.com/word/dehydration
Updated: 2026-05-06

## Definition

a condition where your body loses more water than it takes in. It can make you feel tired, thirsty, or dizzy.

For teachers: a physiological state resulting from an excessive loss of body water. Often used to describe the medical condition or the process of removing moisture from a substance.

## Examples

- Drinking water during a long hike helps prevent dehydration.
- The athlete was treated for severe dehydration after competing in the marathon under the midday sun.
- Clinical dehydration can lead to electrolyte imbalances and impaired cognitive function if not addressed promptly with oral rehydration salts or intravenous fluids.

## Usage notes

- Typically uncountable when referring to the medical state; can be countable in technical contexts referring to specific chemical processes.

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