amyloid

noun

am·​y·​loid ˈa-mə-ˌlȯid How to pronounce amyloid (audio)
: a waxy translucent substance consisting primarily of protein that is deposited in some animal organs and tissues under abnormal conditions (such as Alzheimer's disease) compare beta-amyloid
amyloid adjective

Examples of amyloid in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Researchers at Washington University found markedly different gut microbiomes in people at the earliest preclinical stages of Alzheimer’s, differences correlated with amyloid and tau accumulation before any cognitive symptoms appeared. — Holly Baines, STAT, 14 Oct. 2026 That’s because perimenopause is around the time when brain changes start occurring that could lead towards dementia, like build-up of proteins like taus and amyloids in the brain. — Maggie Ryan, Flow Space, 14 Oct. 2026 Blood tests that measure a tau type called p-tau217 seem particularly good at reflecting amyloid buildup in people with symptoms. — Lauran Neergaard, Los Angeles Times, 15 Sep. 2026 Kisunla is designed to help slow the progression of early symptomatic Alzheimer’s by targeting the brain to break up and remove amyloid plaques, which are a hallmark of the disease. — Lauren Pastrana, Miami Herald, 5 Sep. 2026 See All Example Sentences for amyloid

Word History

First Known Use

1866, in the meaning defined above

Time Traveler
The first known use of amyloid was in 1866

Phrases Containing amyloid

Rhymes for amyloid

See All Rhymes for amyloid

Browse Nearby Words

amylograph
amyloid
amyloid beta
See all Nearby Words

Cite this Entry

“Amyloid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/amyloid. Accessed 20 Oct. 2026.

Copy Citation

Medical Definition

amyloid

noun
am·​y·​loid
ˈam-ə-ˌlȯid
1
: a nonnitrogenous starchy food
2
: a waxy translucent substance consisting primarily of protein that is deposited in some animal organs and tissue under abnormal conditions (as in Alzheimer's disease) see beta-amyloid
amyloid adjective

More from Merriam-Webster on amyloid

Britannica.com: Encyclopedia article about amyloid

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Last Updated: - Updated example sentences

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of compunction

See Definitions and Examples »

Popular in Grammar & Usage

See More

'Affect' vs. 'Effect'

Merriam-Webster’s Great Big List of Words You Love to Hate

The Exceptions of '-s' and '-es' Plurals

Is it 'nerve-racking' or 'nerve-wracking'?

What's the difference between 'fascism' and 'socialism'?
See More

Popular in Wordplay

See More

16 Food Words Recently Added to the Dictionary

The Real Origin of 'Supercalifragilistic'

9 Words That Sound Like Insults But Aren't

7 Words for Bad Endings and Rough Situations

Did 'orange' the fruit or the color come first?
See More

Popular

See More

'Affect' vs. 'Effect'

16 Food Words Recently Added to the Dictionary

The Real Origin of 'Supercalifragilistic'
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
artwork of illustrated limes with the text limes and smile with an arrow connecting the two words
Quiz: Spot the Anagram! Scramble these words to find new words with the e...
See All