dehydration

Meaning of dehydration: Dehydration affects infants, older adults, and people with chronic illness disproportionately, since each group is less able to compensate for fluid losses.

Definition of dehydration

Dehydration is a condition that occurs when the body loses more water than it takes in, reducing the total amount of fluid available to maintain normal function. It can result from inadequate fluid intake, excessive fluid loss, or both occurring together, with common causes including prolonged vomiting or diarrhea, excessive sweating, fever, and certain medications that increase urination.

As dehydration develops, the body attempts to compensate by reducing urine output and by shifting fluid between different body compartments, but as fluid losses continue, these compensating mechanisms become less effective, and signs such as thirst, dry mouth, reduced urination, and fatigue can appear and progress in severity.

Because infants, older adults, and people with certain chronic illnesses have less physiological reserve to compensate for fluid loss, dehydration can develop more quickly and become more severe in these groups than in an otherwise healthy adult experiencing the same degree of fluid loss.

How dehydration is built

de hydr ation dehydration
  • de- Prefix · Latin down, away from, removal of
  • hydr/o Combining form · Greek water, fluid
  • -ion, -ation Suffix · Latin process, action, or its result

A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.

Used in a sentence

The patient was treated for dehydration following several days of persistent vomiting.

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Good to know

Infants and older adults are disproportionately affected by dehydration because both groups have reduced physiological reserve to compensate for fluid loss, a vulnerability distinct from simply losing fluid faster.

Word origin

Where “dehydration” comes from

Formed from Latin de-, meaning removal, and Greek hydor, meaning water, combined with the suffix -ation.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.