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

The mustached southerner, yachting enthusiast and philanthropist, whose empire also included sports clubs, had been suffering from the degenerative disease Lewy Body Dementia.

From Barron's • May 6, 2026

Prof Bart De Strooper, from the UK Dementia Research Institute at UCL, said the review "does not clarify the evidence, it blurs it" and added that "the flaw in this review is fundamental".

From BBC • Apr. 16, 2026

Dementia can cause many symptoms, including physical and verbal aggression and a short temper, especially as the condition worsens.

From MarketWatch • Mar. 3, 2026

Dementia involves a decline in thinking and memory severe enough to interfere with daily life and independent living.

From Science Daily • Feb. 11, 2026

Multos da Jupiter annos, Dementia quanta est hominum, turpissima vota diis insusurrant, si quis admoverit aurem, conticescunt; et quod scire homines nolunt, Deo narrant.

From The Anatomy of Melancholy by Burton, Robert

Related Words

• brain damage
• mental disorder