dementia

American  

[dih-men-shuh, -shee-uh] / dɪˈmɛn ʃə, -ʃi ə /

noun

1. a condition characterized by progressive, persistent, severe impairment of intellectual capacity, including memory loss, confusion, and emotional instability, resulting from the loss of or damage to neurons in the brain.

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dementia British  

/ -ʃɪə, dɪˈmɛnʃə /

noun

1. a state of serious emotional and mental deterioration, of organic or functional origin

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dementia Scientific  

/ dĭ-mĕn′shə /

1. Deterioration of intellectual faculties, such as memory, concentration, and judgment, sometimes accompanied by emotional disturbance and personality changes. Dementia is caused by organic damage to the brain (as in Alzheimer's disease), head trauma, metabolic disorders, or the presence of a tumor.

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Other Word Forms

• demential
  adjective

Etymology

Origin of dementia

First recorded in 1800–10; from Latin dēmentia “madness,” equivalent to dēment- “out of one's mind” ( see dement) + -ia noun suffix

Compare meaning

How does dementia compare to similar and commonly confused words? Explore the most common comparisons:

• dementia vs. senility

Explanation

If your grandfather suffers from dementia, he has a brain disorder that's causing him to gradually lose his memory and become disoriented and confused. Although dementia is most common in elderly people, it's not a normal part of growing older but a syndrome caused by brain disease or injury. Dementia gets its name from the Latin words de, or "without," and mens, or "mind," which join together to mean "madness," although in English, dementia is not the same thing as madness. One example of an illness that causes dementia is Alzheimer's disease.

Example Sentences

Participants with lower active B12 had a higher volume of white matter lesions, which are areas of brain injury that have been linked to cognitive decline, dementia, and stroke risk.

From Science Daily • May 22, 2026

Clinical trials are in the works; a major one aims to determine if metformin, now approved as a diabetes medication, can delay age-related diseases like cancer and dementia, and improve cardiac health.

From Barron's • May 21, 2026

Jones, best known for his part in the British comedy group Monty Python, died in 2020 aged 77 from a rare form of dementia.

From BBC • May 20, 2026

Around 1 million adults in the U.S. are projected to develop dementia each year by 2060, compared with around 514,000 in 2020, the study found.

From MarketWatch • May 19, 2026

If your aged parents have grown tiresome or incontinent, you put them away where others will deal with their dirty diapers and dementia.

From "Nickel and Dimed: On (Not) Getting By in America" by Barbara Ehrenreich

Related Words

• brain damage
• mental disorder