English Reference

Word

dementia

Phoneticsde·men·tia

US/dɪˈmɛnʃiə/

UK/dɪmˈɛnʃɐ/

Definitions

01medical condition

B2 · Medicine

n. a condition where the brain stops working properly, making it hard to remember things, think clearly, or speak.

n. a progressive decline in cognitive function due to brain damage or disease, affecting memory, attention, and problem-solving. Uncountable in general usage; often used with 'vascular' or 'senile' as modifiers.

“The family noticed the early signs of dementia when he started forgetting where he lived.”

“Recent clinical studies suggest that early intervention can significantly improve the quality of life for patients diagnosed with vascular dementia.”

Usage

Often used as an uncountable noun, though specific types are referred to as 'dementias'.

Synonyms

cognitive declineAlzheimer's

02madness

C2

n. an old-fashioned word for being crazy or losing your mind.

n. a state of madness or insanity. This sense is largely historical and rarely appears in modern clinical or legal contexts.

“In the old story, the king fell into a deep dementia after losing his crown.”

“The poet described a world descending into a collective dementia, where reason was abandoned for chaos.”

Archaic · Literary

Teaching tip

This sense is archaic; in modern English, 'dementia' is almost exclusively a medical term for cognitive decline in the elderly.

Antonyms

Real-World Examples

“This surprising shift may help explain how normal aging sets the stage for Alzheimer’s disease and dementia.”
ScienceDaily · 7 Aug 2026
“Numerous studies have shown that people with dementia are prone to refuse medical and wider forms of care.”
The Guardian · 4 Aug 2026
“Brain diseases, such as dementia, can also leave people unaware of the heat or unable to do anything about it.”
BBC News · 22 Jun 2026

Etymology

Borrowed from Latin dementia.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Collocations

dementia risk

This entry

Level
B2 · Upper Intermediate
Frequency
Frequent
Updated

Scan code

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English Reference