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

Croft and Neale know they aren’t necessarily close to the finish line when it comes to curing dementia.

From Los Angeles Times • May 18, 2026

A newlywed bride was given the gift of two weddings in two days so her grandfather with dementia could walk her down the aisle from his care home.

From BBC • May 18, 2026

“I wouldn’t be in this field of work if I didn’t think we were pushing towards solutions that can slow down dementia, treat dementia, cure dementia,” Croft said.

From Los Angeles Times • May 18, 2026

She said occasions like hers can be "really special" for people who have family members with dementia, despite people with the disease often experiencing memory loss.

From BBC • May 18, 2026

The doctor also said the dementia would progress and that Walter would likely become incapacitated.

From "Just Mercy" by Bryan Stevenson

Related Words

• brain damage
• mental disorder