plaque

noun

1
a
: an ornamental brooch
especially : the badge of an honorary order
b
: a flat thin piece (as of metal) used for decoration
c
: a commemorative or identifying inscribed tablet
2
a
: a localized abnormal patch on a body part or surface
b
: a sticky usually colorless film on teeth that is formed by and harbors bacteria
c
: an atherosclerotic lesion
d
: a histopathologic lesion of brain tissue that is characteristic of Alzheimer's disease and consists of a dense proteinaceous core composed primarily of beta-amyloid that is often surrounded and infiltrated by a cluster of degenerating axons and dendrites
3
: a clear area in a bacterial culture produced by viral destruction of cells

Examples of plaque in a Sentence

A bronze plaque marked the city's oldest building. They gave him a plaque in honor of his 30 years of service. Brushing your teeth prevents the buildup of plaque. The scientists are studying the way the plaques form.
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.
Since 1986, more than 500 plaques have been presented. Courier-News, Chicago Tribune, 16 Apr. 2025 There's never been a plaque on the gray stone and slate residence at the northwest corner of Saint Paul and 29th streets. Jacques Kelly, Baltimore Sun, 12 Apr. 2025 Bacteria within the plaque and tartar can irritate the gums and teeth, triggering inflammation in the body.95 The most common cause of plaque and tartar buildup in the mouth is poor oral hygiene. Cristina Mutchler, Health, 12 Apr. 2025 The values your company upholds should be perceivable in everyone's actions, not just as text on your website or plaques in your office. Stoyan Mitov, Forbes.com, 8 Apr. 2025 See All Example Sentences for plaque

Word History

Etymology

French, from Middle French, metal sheet, from plaquer to plate, from Middle Dutch placken to piece, patch; akin to Middle Dutch placke piece, Middle High German placke patch

First Known Use

1845, in the meaning defined at sense 1a

Time Traveler
The first known use of plaque was in 1845

Browse Nearby Words

Cite this Entry

“Plaque.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/plaque. Accessed 25 Apr. 2025.

Kids Definition

plaque

noun
1
: an ornamental pin
especially : an honorary badge
2
: a flat thin piece (as of metal) used for decoration or inscribed as a memorial or marker
3
: a sticky usually colorless film on teeth that is formed by and contains bacteria

Medical Definition

plaque

noun
variants also placque
1
a
: a localized abnormal patch on a body part or surface and especially on the skin
psoriatic plaque
b
: a sticky usually colorless film on teeth that is formed by and harbors bacteria
c
: an atherosclerotic lesion
d
: a histopathologic lesion of brain tissue that is characteristic of Alzheimer's disease and consists of a dense proteinaceous core composed primarily of beta-amyloid that is often surrounded and infiltrated by a cluster of degenerating axons and dendrites

called also senile plaque

2
: a visibly distinct and especially a clear or opaque area in a bacterial culture produced by damage to or destruction of cells by a virus

More from Merriam-Webster on plaque

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