dehydration

dehydration — noun

1. a harmful physical state in which the body contains less water than it needs to

1.nounB2
Definition

a harmful physical state in which the body contains less water than it needs to work properly, often caused by illness, sweating, or not drinking enough fluids

Example

The nurse said the baby was suffering from mild dehydration after the fever.

often modified by 'mild / severe / chronic'

Noor's doctor warned her that dehydration could make her feel dizzy and confused.

Common collocations
  • mild dehydration
  • severe dehydration
  • chronic dehydration
  • suffer from dehydration
  • prevent dehydration
  • signs of dehydration
  • risk of dehydration
  • treat dehydration
Synonyms
  • fluid loss

    a more general term that can refer to losing water from any fluid system, not just the body

  • desiccation

    more technical and usually describes extreme drying of materials or tissue, rarely used in everyday health contexts

  • water depletion

    sounds more scientific; often used in sports medicine or nutrition writing

Antonyms
  • hydration

    the healthy state of having enough water in the body

Grammar Patterns

noun used without an article in general statements

often modified by adjectives: mild / severe / chronic dehydration

Usage Note

Commonly paired with adjectives that indicate severity: 'mild', 'moderate', or 'severe'. In medical writing, 'dehydration' is an uncountable noun and rarely takes an article.

Common Mistakes

I have a dehydration.
I have dehydration.
'dehydration' is an uncountable noun and does not take 'a'.
She felt thirst but it was not dehydration yet.
She felt thirsty, but she was not dehydrated yet.
'thirst' is the feeling; 'dehydration' is the physical condition.

2. a method or process of taking water out of a substance such as food, so that it

2.nounB2
Definition

a method or process of taking water out of a substance such as food, so that it lasts longer without spoiling or changes into a different form

Example

The factory uses a machine that dries fruit through dehydration, turning it into a light powder.

pattern: through dehydration (method / process)

In cooking class, Sahil learned about food dehydration and started making dried apples at home.

Common collocations
  • food dehydration
  • dehydration process
  • dehydration method
  • dehydration of fruit
  • through dehydration
  • freeze dehydration
Synonyms
  • drying

    simpler, everyday word; 'dehydration' is more formal and technical

  • desiccation

    scientific term for thorough drying, often used in chemistry and biology

  • water extraction

    describes the action rather than the purpose (preservation)

Antonyms
  • rehydration

    the process of adding water back to dried material

Grammar Patterns

noun + of + something: dehydration of [food / material]

Usage Note

Frequently followed by 'of' to specify the material being dried ('dehydration of fruit'). In food science contexts, it contrasts with 'freeze-drying' and 'air-drying' as specific techniques.

Common Mistakes

The dehydration of the sick child worried the doctors.' (meaning medical condition) — This sentence mixes sense 2 with sense 1.
Use sense 1 for the medical condition: 'The child's dehydration worried the doctors.' The process sense is for food or materials.
I bought a dehydration for my kitchen.
I bought a dehydrator for my kitchen.
'dehydration' is the process; 'dehydrator' is the machine.

Word family

  • dehydrate
    verbB2
  • dehydrated
    adjectiveB2
  • dehydrator
    nounC1
  • hydration
    nounB2
  • hydrate
    verbB2
  • rehydrate
    verbC1
  • rehydration
    nounC1

Synonym discussion

Sense: noun/1

'Dehydration' (sense 1, BODY WATER LOSS) refers specifically to the physical condition of having too little water in the body to function normally, and is a medical status that can range from mild to life-threatening. 'Thirst,' by contrast, is the sensation or urge to drink — it is a symptom of dehydration but can also occur without dehydration (e.g., after eating salty food). 'Desiccation' belongs to scientific and technical language, describing extreme drying of any material (including soil, tissue samples, or food); it is rarely used in everyday health conversations. 'Water loss' is a broader, non-technical phrase that can apply to any situation where water is removed (from soil, a swimming pool, or the body), whereas 'dehydration' in its medical sense is almost exclusively attached to living organisms. For example: 'After the long run, Noor felt thirsty and drank some water' (thirst as a feeling). 'The patient was hospitalised for severe dehydration and needed IV fluids' (dehydration as a diagnosed condition).

thirst ↗desiccationwater loss

Common collocations

Nouns

Adverbs

Phrases

  • risk of dehydration
  • signs of dehydration
  • suffer from dehydration
  • prevent dehydration
  • through dehydration
  • dehydration process

Prepositions

Etymology

GreekLatinFrenchEnglish

The word 'dehydration' was formed in English in the mid-1800s by combining the Latin prefix 'de-' (meaning 'away from' or 'removing') with the Greek root 'hydr-' (from 'hydor,' meaning 'water') and the suffix '-ation' (which turns a verb into a noun meaning 'a process or state'). So the word's literal building blocks mean 'the process of taking water away from something.' The medical sense — a dangerous lack of water in the body — became common in the early 1900s as doctors began to recognize and name the condition separately from simple thirst.