What does dehydration mean?
Dehydration is most commonly the medical condition that results when the body loses or fails to receive enough water and other fluids. It may occur because of intense sweating, vomiting, diarrhea, fever, insufficient drinking, or increased urination, and it can affect people of any age. Symptoms can include thirst, dry mouth, reduced urination, fatigue, dizziness, and confusion, with severe dehydration requiring prompt treatment. The word also describes removing moisture from food, as in the dehydration of fruit for preservation, and can describe the drying of soil or landscapes. In figurative use, it may suggest the loss of vitality, richness, or life. Understanding the word is useful because even mild fluid loss can affect comfort and performance, while severe dehydration can become dangerous.
nounThe condition of having lost too much water or fluid, usually through inadequate fluid intake, illness, sweating, or increased urination. The word can also refer to the process of removing water from a substance, especially food, to preserve it.
- The condition of insufficient water or fluid in the body, caused by inadequate intake, excessive loss, or an underlying illness.
- The process of removing water from a substance, especially food, in order to preserve it or make it more concentrated.
- The drying or loss of moisture in a landscape, object, or other system, sometimes used figuratively.
"The hikers were treated for severe dehydration after spending too long in the heat without drinking."
"Children can develop dehydration quickly during a bout of vomiting or diarrhea."
"Slicing fruit and placing it in a dehydrator produces dried fruit through controlled dehydration."
The plural is uncommon and is used mainly for separate cases, episodes, or processes of dehydration.
"The report documented several dehydrations among runners during the heatwave."
Thirst is often the body's alarm bell: by the time you feel it, dehydration may already be underway.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does dehydration come from?
Dehydration was formed in English from the combining form de-, meaning removal or reversal, and hydration. Hydration is based on hydrate, ultimately connected with the Greek hydor, meaning “water.” The same Greek element appears in related words such as hydrogen, in which it is combined with a word meaning “forming.” The prefix de- gives the term its central sense of taking water away or depriving something of water.
Related word forms
How dehydration is actually used
In medical and public-health contexts, dehydration usually refers to a deficiency of body water and fluid. In food and environmental contexts, it more often denotes the deliberate removal or loss of moisture. The noun is generally used as an uncountable concept, though the plural form is occasionally used for separate cases or instances.
Easily confused with dehydration
Dehydration is usually a noun meaning the state of losing too much water or the process of removing water, whereas dehydrate is a verb meaning to cause something to lose water.