dementia

American  

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

noun

dementias plural

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

Derived Forms

• demential
  adjective

Inflected Forms

Nouns

• dementias
  plural

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

McGrail used the perk to take two weeks off work to help her father, who has developed dementia, transition back home after spending time in a rehabilitation center following a bad fall.

From MarketWatch • Jul. 7, 2026

She dotes on her husband, who suffers from dementia and comes to terms with all the paraphernalia and recordings from her career that she hoarded for decades.

From Los Angeles Times • Jul. 7, 2026

Understanding what protects these individuals could eventually point scientists toward new ways to treat or even prevent dementia.

From Science Daily • Jul. 3, 2026

Attorneys can work specific language about dementia care into advance directives, but for many people, having a dementia directive as an addendum is a cost-effective option.

From The Wall Street Journal • Jul. 3, 2026

Alyce often visits an uncle with dementia who lives in a nursing home in Tustin—a community right in the heart of the affected area.

From "Dry" by Neal Shusterman and Jarrod Shusterman

Related Words

• brain damage
• mental disorder